JP5785812B2 - 2-wire welding control method - Google Patents

Description

  The present invention relates to a two-wire welding control method in which an arc is generated between a consumable electrode and a base material to form a molten pool, and welding is performed while a filler wire is inserted into the latter half of the molten pool.

  A two-wire welding method in which an arc is generated between a consumable electrode (hereinafter referred to as a welding wire) and a base material to form a molten pool, and a filler wire is inserted into the molten pool for welding (see Patent Document 1). Is conventionally known. In this two-wire welding method, since the molten metal of the filler wire is added to the molten metal of the welding wire, the amount of the molten metal is increased, and high-speed welding can be performed with high welding. In particular, when high-speed welding is performed by the two-wire welding method, it is important to feed the filler wire by short-circuiting it from the rear side of the consumable electrode arc to the molten pool in order to prevent a humping bead. This is because when the filler wire is fed into the consumable electrode arc and melted, the molten pool is hardly cooled and the swell of the latter half of the molten pool cannot be suppressed by the filler wire, thereby suppressing the humping bead. This is because there is no effect. On the other hand, if the filler wire is short-circuited to the second half of the molten pool at the arc peripheral portion and fed and melted by the heat of the molten pool, the molten pool is cooled, and the filler wire cools the second half of the molten pool. The portion is suppressed and the formation of the humping bead can be suppressed. Therefore, in the two-wire welding method of the prior art, the molten pool is cooled by short-circuiting the filler wire in a cold state without passing a current through the filler wire.

  In the two-wire welding method, various consumable electrodes such as a carbon dioxide arc welding method, a mag welding method, a MIG welding method, a pulse arc welding method, and an AC arc welding method are used as a method for generating an arc between the welding wire and the base material. A type arc welding process can be used. Further, the filler wire basically has a wire tip short-circuited with the molten pool, and is melted by heat from the molten pool. Therefore, no arc is generated between the filler wire and the molten pool. In this invention, although the case where a pulse arc welding method is used as said consumable electrode type arc welding method is demonstrated, another welding method may be sufficient. Moreover, in the following description, the base material and the molten pool are used in substantially the same meaning.

  FIG. 6 is a current / voltage waveform diagram in the two-wire welding method using pulse arc welding. The figure (A) shows the time change of the welding current Iw which energizes a welding wire, the figure (B) shows the time change of the welding voltage Vw applied between a welding wire and a base material (molten pool), FIG. 5C shows the change over time of the filler wire feed speed Fw. Although the welding wire feeding speed is not shown, it is fed at a constant value at a constant speed. No voltage is applied between the filler wire and the molten pool, and no current is applied. As described above, the filler wire is fed in a state of being short-circuited with the molten pool. Even if the filler wire is separated from the molten pool, no voltage is applied, so no arc is generated between the filler wire and the molten pool. Hereinafter, a description will be given with reference to FIG.

  During the peak period Tp from time t1 to t2, a peak current Ip having a large current value equal to or higher than the critical value is energized to transfer droplets from the welding wire as shown in FIG. ), A peak voltage Vp proportional to the arc length is applied between the welding wire and the molten pool.

  During the base period Tb from time t2 to t3, as shown in FIG. 5A, the base current Ib having a small current value less than the critical value is energized in order to prevent the formation of droplets. ), The base voltage Vb is applied. Welding is performed by repeating the period from time t1 to t3 as one period (pulse period Tf). The peak current Ip is about 450 to 550 A, and the base current Ib is about 30 to 60 A. During the peak period Tp from time t3 to t4 and the base period Tb from time t4 to t5, the same operation is repeated again.

  On the other hand, as shown in FIG. 5C, the filler wire feed speed Fw is fed at a constant filler wire feed speed Fc in a short-circuited state with the molten pool. The steady filler wire feeding speed Fc is often set to a range of about 10 to 30% of the welding wire feeding speed in order to melt stably.

  By the way, in order to perform good pulse arc welding, it is important to maintain the arc length at an appropriate value. In order to maintain the arc length at an appropriate value, the following output control (arc length control) of the welding apparatus is performed. The arc length is substantially proportional to the welding voltage average value Vav indicated by a broken line in FIG. For this purpose, the welding voltage average value Vav is detected, and the output for changing the welding current average value Iav indicated by the broken line in FIG. 5A so that the detected value becomes equal to the welding voltage set value corresponding to the appropriate arc length. Take control. When the welding voltage average value Vav is larger than the welding voltage set value, the arc length is longer than the appropriate value. Therefore, the welding current average value Iav is decreased to reduce the wire melting rate and shorten the arc length. To do. On the other hand, when the welding voltage average value Vav is smaller than the welding voltage set value, the arc length is shorter than the appropriate value, so the welding current average value Iav is increased to increase the wire melting rate and the arc length is increased. Like that. As the welding voltage average value Vav, a value obtained by passing the welding voltage Vw through a low-pass filter (cutoff frequency of about 1 to 10 Hz) is generally used. Further, as an operation amount for changing the welding current average value Iav, changing at least one of the peak period Tp, the pulse period Tf, the peak current Ip, or the base current Ib is performed. For example, when feedback control is performed using the pulse period Tf as an operation amount, the peak period Tp, the peak current Ip, and the base current Ib are set to predetermined values (referred to as a frequency modulation control method). When feedback control is performed using the peak period (pulse width) Tp as an operation amount, the peak current Ip, the base current Ib, and the pulse period Tf are set to predetermined values (referred to as a pulse width modulation control method).

  In the invention of Patent Document 2, in gas shield metal arc welding of a zinc-based plated steel sheet, a plurality of wires are used, an arc is generated only on the preceding wire to form a molten pool, and a subsequent wire is placed on the molten pool. Is inserted at a distance of 2 mm or more, and is vibrated and stirred under the conditions of a frequency of 0.5 times / second or more and an amplitude of 0.3 mm or more, and an argon gas containing less than 7 Vol% oxygen is used as a shielding gas. A gas shielded metal arc welding method characterized by: The vibration direction of the trailing wire may be a welding line direction, a direction perpendicular to the welding line, or an arc. According to the method of the present invention, in gas shield metal arc welding of a zinc-based plated steel sheet that generates a large amount of gas during welding, generation of pits and blowholes can be prevented and a sound weld metal can be obtained. That is, the invention of Patent Document 2 is a two-wire welding method using two welding wires, in which an arc is generated on a preceding wire (consumable electrode) to form a molten pool, and a trailing wire (filler wire). In this method, the weld pool is stirred by vibrating (weaving) in the direction of the weld line without generating an arc.

JP 2010-1647489 A Japanese Patent Laid-Open No. 6-39554

In the above-described conventional 2-wire welding method, the filler wire is inserted in a state of being short-circuited with the molten pool, and the filler wire is melted by the heat of the molten pool. For this reason, the feeding speed of the filler wire is set so as to balance with the speed (melting speed) at which the filler wire is melted by the heat of the molten pool. Therefore, the maximum value of the feeding speed of the filler wire is a value at which the filler wire can be melted by the heat from the molten pool. When the feeding speed of the filler wire becomes larger than this maximum value, the filler wire remains undissolved, resulting in a defective bead. On the other hand, in the two-wire welding method, in order to further improve high welding and high-speed welding, it is necessary to further increase the feeding speed of the filler wire.

  Therefore, in the present invention, the formation of the humping bead is suppressed by cooling the latter half of the molten pool and suppressing the rise, and the filler wire feeding speed is increased under high melting conditions to achieve high welding. An object of the present invention is to provide a two-wire welding control method capable of achieving the above.

In order to solve the above-mentioned problems, the invention of claim 1 is directed to welding while forming a molten pool by generating an arc between the consumable electrode and the base material and inserting a filler wire into the latter half of the molten pool. In the two-wire welding control method,
Weaving the insertion position of the filler wire in the front-rear direction of the welding direction, and changing the feeding speed of the filler wire in synchronization with the weaving,
This is a two-wire welding control method.

According to a second aspect of the present invention, the displacement amount when the insertion position is displaced in the front direction relative to the central position of the weaving is a positive value, and the displacement amount when the insertion position is displaced in the rear direction is negative. And changing the feeding speed of the filler wire in proportion to the amount of displacement,
The two-wire welding control method according to claim 1.

The invention of claim 3 provides a predetermined delay time between the two signals when the feeding speed of the filler wire is changed in proportion to the amount of displacement.
The two-wire welding control method according to claim 2.

According to a fourth aspect of the present invention, the filler wire feeding speed when the filler wire feeding speed is displaced in the rearward direction when the insertion position is displaced in the frontward direction relative to the weaving center position. Faster than
The two-wire welding control method according to claim 1.

  According to the present invention, the filler wire insertion position is weaved in the front-rear direction of the welding direction, and the filler wire feeding speed is changed in synchronization with the weaving. As a result, when the filler wire insertion position is in the forward direction, the filler wire is accelerated to increase the average value of the filler wire feeding speed, and when it is in the rear direction, the molten pool is cooled and raised. It suppresses the formation of humping beads. As a result, in the present invention, it is possible to perform high-weld welding and high-speed welding as compared with the prior art.

It is a schematic diagram of the welding part which shows the 2 wire welding control method which concerns on embodiment of this invention. It is a waveform diagram of the 1st pattern which shows the 2 wire welding control method concerning an embodiment of the invention. It is a waveform diagram of the 2nd pattern which shows the 2 wire welding control method concerning an embodiment of the invention. It is a waveform diagram of the 3rd pattern which shows the 2 wire welding control method concerning an embodiment of the invention. It is a block diagram of the welding apparatus for enforcing the 2-wire welding control method which concerns on embodiment of this invention mentioned above in FIGS. In a prior art, it is an electric current and a voltage waveform diagram in the 2 wire welding method using pulse arc welding.

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

  FIG. 1 is a schematic diagram of a welded portion showing a two-wire welding control method according to an embodiment of the present invention. This figure is a view of the welded portion from the side, and welding proceeds in the left direction as indicated by an arrow. Hereinafter, a description will be given with reference to FIG.

  A welding wire 1 is fed from a welding torch 4, and an arc 3 is generated between the tip of the welding wire and the base material 2. Here, the advance angle of the welding torch 4 is 0 °, and the welding wire 1 is fed vertically to the base material 2. The arc 3 forms a molten pool 2 a in the base material 2. A center line indicating the feeding direction of the welding wire 1 is indicated by a one-dot chain line, and a point where the center line intersects the surface of the base material 2 is a welding target position a.

  The filler wire 6 is fed through the filler wire guide 7 and inserted into the insertion reference position b0 in the latter half of the molten pool 2a in a short-circuited state. The distance between the welding target position a and the insertion reference position b0 is the inter-wire distance Lw (mm). Further, the filler wire 6 is weaved at a predetermined amplitude Sw (mm) and a predetermined weaving frequency f (Hz) in the front-rear direction of the welding direction. Therefore, as shown by the left arrow and the right arrow, the insertion position of the filler wire 6 is weaved with the amplitude Sw as the insertion reference position b0 as the weaving center position, the frontmost position is b1, and the rearmost position. Becomes b2. The distance between the points b1 and b2 is the amplitude Sw. The foremost position b1 is set in a range behind the welding target position a and ahead of the arc generation part. Further, the rearmost position b2 is set in front of the rear end of the molten pool 2a. For example, the inter-wire distance Lw is set to about 3 to 6 mm, the amplitude Sw is set to about 3 to 6 mm, and the weaving frequency f is set to about 5 to 50 Hz. These values are set to appropriate values by experiments according to the feeding speed, diameter, material, welding speed, joint shape, etc. of the welding wire.

The distance between the insertion position of the filler wire 6 displaced by weaving and the insertion reference position (weaving center position) b0 is defined as a displacement Lh (mm). The sign of the displacement Lh is a positive value before the insertion reference position b0 and a negative value behind it. With this definition, the foremost position b1 is Lh = Sw / 2, the insertion reference position (weaving center position) b0 is Lh = 0, and the rearmost position b2 is Lh = −Sw / 2. Here, it is assumed that the displacement amount Lh changes in a sine wave shape as in the following equation.
Lh = (Sw / 2) · sin (2 · π · f · t) (1) Equation t is the elapsed time (seconds).
Then, the feeding speed Fw of the filler wire 6 changes in synchronization with the displacement amount Lh. Hereinafter, the change pattern of the feeding speed Fw of the filler wire 6 will be described with reference to FIGS.

  FIG. 2 is a waveform diagram of a first pattern showing the two-wire welding control method according to the embodiment of the present invention. The figure (A) shows the time change of the welding current Iw which energizes a welding wire, the figure (B) shows the time change of the welding voltage Vw applied between a welding wire and a base material (molten pool), FIG. 6C shows the change over time of the displacement Lh of the filler wire insertion position, and FIG. 6D shows the change over time of the filler wire feed speed Fw. Although the welding wire feeding speed is not shown, it is fed at a constant value at a constant speed. No voltage is applied between the filler wire and the molten pool, and no current is applied. This figure is a waveform diagram in the case where the time axis (horizontal axis) is 10 times or longer than that in FIG. Therefore, the welding current Iw shown in FIG. 6A is essentially the same pulse waveform as that in FIG. 6, but the average value thereof is displayed, so that it is a substantially straight line. Similarly, the welding voltage Vw shown in FIG. 5B is also a pulse waveform, but it is an almost straight line because it displays an average value. Hereinafter, a description will be given with reference to FIG.

  As shown in FIG. 6A, a welding current Iw is applied to the welding wire, and as shown in FIG. 5B, a welding voltage Vw is applied between the welding wire and the base metal, and an arc is generated. Has occurred. As shown in FIG. 6C, the displacement amount Lh changes in a sine wave shape as shown in the above equation (1). Therefore, at time t0, t = 0 seconds and Lh = 0. At time t1, t = 1 / (4 · f), and the displacement Lh = Sw / 2. At time t2, t = 1 / (2 · f), and the displacement amount Lh = 0. At time t3, t = 3 / (4 · f), and the displacement Lh = −Sw / 2. At time t4, t = 1 / f, and the displacement amount Lh = 0. From this point on, it is repeated. For example, when f = 10 Hz, time t1 = 25 ms, time t2 = 50 ms, time t3 = 75 ms, and time t4 = 100 ms.

As shown in FIG. 4D, the filler wire feed speed Fw changes in a sinusoidal form as shown in the following equation in proportion to the displacement Lh.
Fw = (Sf / 2) · sin (2 · π · f · t) + Fwc (2) where Sf (cm / min) is the feed speed amplitude and f (Hz) is the weaving frequency. , T (seconds) is the elapsed time, and Fwc (cm / min) is the amplitude center feeding speed.
At time t0, t = 0 seconds, and the filler wire feed speed Fw = Fwc. At time t1, t = 1 / (4 · f), and the filler wire feed speed Fw = (Sf / 2) + Fwc. At time t2, t = 1 / (2 · f), and the filler wire feed speed Fw = Fwc. At time t3, t = 3 / (4 · f), and the filler wire feed speed Fw = (− Sf / 2) + Fwc. At time t4, t = 1 / f, and the filler wire feed speed Fw = Fwc. From this point on, it is repeated.

  As shown in FIGS. 3C and 3D, the change in the filler wire feed speed Fw is proportional to the displacement Lh of the filler wire insertion position. Here, the amplitude center feeding speed Fwc can be set to a value larger than the steady filler wire feeding speed Fc in the prior art described above with reference to FIG. Since the amplitude center feeding speed Fwc is an average value of the feeding speed, this embodiment can set the feeding speed of the filler wire larger than that of the prior art. The reason for this is as follows. During the period from time t0 to t2, the displacement amount Lh ≧ 0, and the filler wire insertion position enters the interior of the arc generator or approaches the arc generator, so the heat input to the filler wire increases and melts. Increases speed. Therefore, during this period, the filler wire can be melted even if the feeding speed of the filler wire is increased. During the period from the time t2 to the time t4, the displacement amount Lh <0 and the filler wire insertion position moves away from the arc generating portion, so that the filler wire melting speed becomes small, and the filler wire feeding speed is also proportional. It is small. The filler wire is melted by receiving heat from the molten pool. For this reason, as above-mentioned, the effect | action which suppresses cooling and a rise of a molten pool acts, and formation of a humping bead can be suppressed. That is, when the insertion position is in the front direction (Lh ≧ 0), the melting of the filler wire is promoted to increase the average value of the feeding speed of the filler wire, and when it is in the rear direction (Lh <0) Humping bead formation is suppressed by suppressing cooling and rising of the pond. As a result, in this embodiment, it becomes possible to perform high-weld welding and high-speed welding as compared with the prior art. In addition, since the filler wire only needs to promote melting when it is in the front direction, it does not need to be in a short circuit state with the molten pool. Instead, when the insertion position of the filler wire is within the generation of the arc, it is preferable that the filler wire is in a non-short-circuit state in order to melt stably. On the other hand, when the insertion position of the filler wire is in the rear direction, in order to receive heat from the molten pool and to suppress the rise, it is an essential condition to be in a short-circuit state.

  FIG. 3 is a waveform diagram of a second pattern showing the two-wire welding control method according to the embodiment of the present invention. The figure (A) shows the time change of the welding current Iw which energizes a welding wire, the figure (B) shows the time change of the welding voltage Vw applied between a welding wire and a base material (molten pool), FIG. 6C shows the change over time of the displacement Lh of the filler wire insertion position, and FIG. 6D shows the change over time of the filler wire feed speed Fw. This figure corresponds to FIG. 2 described above and is the same except for the filler wire feeding speed Fw shown in FIG. Hereinafter, a change pattern of the feeding speed Fw of the filler wire will be described with reference to FIG.

As shown in FIG. 4D, the filler wire feed speed Fw is sinusoidal as shown in the following equation corresponding to the change in the displacement Lh of the filler wire insertion position shown in FIG. Change.
Fw = (Sf / 2) · sin (2 · π · f · t−α) + Fwc (3) where α (second) is a predetermined delay time. That is, the filler wire feed speed Fw is a sine wave delayed by the delay time α from the displacement amount Lh. It is set to about 0 <α ≦ (1/8 · f). In the case of f = 10 Hz, the upper limit value of α is 1/8 · 10 = 12.5 ms. The waveform in FIG. 4D is for the case where α = (1/8 · f). Accordingly, as shown in FIG. 4D, t = (1/8 · f) seconds in the middle between time t0 and time t1, and the filler wire feed speed Fw = Fwc. In the middle between time t1 and time t2, t = (3/8 · f), and the filler wire feed speed Fw = (Sf / 2) + Fwc. In the middle between time t2 and time t3, t = (5/8 · f), and the filler wire feed speed Fw = Fwc. In the middle between time t3 and time t4, t = (7/8 · f), and the filler wire feed speed Fw = (− Sf / 2) + Fwc. At the time when (1/8 · f) has elapsed from time t4, t = (9/8 · f), and the filler wire feed speed Fw = Fwc. From this point on, it is repeated.

  As shown in FIGS. 3C and 3D, the change in the filler wire feed speed Fw changes in synchronization with the displacement Lh of the filler wire insertion position and is delayed by the delay time α. It becomes. The effect of synchronizing is the same as in FIG. Furthermore, by delaying, the amplitude center feeding speed Fwc can be further increased, and the average value of the feeding speed of the filler wire can be increased. Thereby, high welding and high-speed welding can be further improved. The reason is that there is a time delay from when the filler wire receives heat from the arc and the molten pool until it contributes to the melting of the filler wire. Therefore, if the feeding speed of the filler wire is changed with a delay time α corresponding to this time delay, the melting efficiency can be improved and the feeding speed of the filler wire can be increased. Therefore, the delay time Α is set corresponding to the time delay between heat input and melting, and is set to an appropriate value by experiment according to the feeding speed, diameter, material, welding speed, etc. of the welding wire.

  FIG. 4 is a waveform diagram of a third pattern showing the two-wire welding control method according to the embodiment of the present invention. The figure (A) shows the time change of the welding current Iw which energizes a welding wire, the figure (B) shows the time change of the welding voltage Vw applied between a welding wire and a base material (molten pool), FIG. 6C shows the change over time of the displacement Lh of the filler wire insertion position, and FIG. 6D shows the change over time of the filler wire feed speed Fw. This figure corresponds to FIG. 2 described above and is the same except for the filler wire feeding speed Fw shown in FIG. Hereinafter, a change pattern of the feeding speed Fw of the filler wire will be described with reference to FIG.

As shown in FIG. 4D, the filler wire feeding speed Fw is in the form of a rectangular wave as shown in the following equation corresponding to the change in the displacement Lh of the filler wire insertion position shown in FIG. Change.
When Lh ≧ 0, Fw = (Sf / 2) + Fwc (41) Formula When Lh <0, Fw = (− Sf / 2) + Fwc (42) In other words, the insertion position of the filler wire in the front direction by weaving ( When Lh ≧ 0), the heat input increases as it approaches the arc, so the feeding speed Fw of the filler wire is increased. On the other hand, when the insertion position of the filler wire is in the rear direction (Lh <0), the heat input is reduced away from the arc, so the feeding speed Fw of the filler wire is reduced. As shown in FIG. 4D, during the period from time t0 to time t2, since the displacement amount Lh ≧ 0, the filler wire feed speed Fw = (Sf / 2) + Fwc. During the period from the time t2 to the time t4, since the displacement amount Lh <0, the filler wire feed speed Fw = (− Sf / 2) + Fwc. From this point on, it is repeated.

  As shown in FIGS. 3C and 3D, the filler wire feed speed Fw changes in a rectangular wave shape in synchronization with the change in the displacement amount Lh of the filler wire insertion position. The effect of doing this is the same as in FIG. However, since the feeding speed Fw of the filler wire is changed to a rectangular wave shape, the filler wire feeding control circuit is simplified as compared with the case where the filler wire feeding speed Fw is changed to a sine wave shape as in FIG.

  2 to 4 described above, the case where the displacement amount Lh of the filler wire insertion position due to weaving changes in a sine wave shape has been described. However, the displacement amount Lh may be changed to a triangular wave, a trapezoidal wave, or a rectangular wave. Correspondingly, the feeding speed Fw of the filler wire may be changed to a triangular wave or a trapezoidal wave.

  FIG. 5 is a block diagram of a welding apparatus for carrying out the two-wire welding control method according to the embodiment of the present invention described above with reference to FIGS. This figure shows the case where the consumable electrode arc welding is the pulse arc welding described above. Hereinafter, each block will be described with reference to FIG.

  The power supply main circuit PM receives a commercial power supply (not shown) such as a three-phase 200 V as input, performs output control by inverter control according to a drive signal Dv described later, and generates a welding voltage Vw and a welding current Iw for generating the arc 3. Is output. Although not shown, this power main circuit PM is a primary rectifier circuit that rectifies commercial power, a capacitor that smoothes the rectified direct current, and an inverter circuit that converts the smoothed direct current into high frequency alternating current according to the drive signal Dv. And a high-frequency transformer that steps down the high-frequency alternating current to an appropriate voltage value for generating the arc 3, a secondary rectifier circuit that rectifies the stepped-down high-frequency alternating current, and a reactor that smoothes the rectified direct current.

  The welding wire 1 is fed through the welding torch 4 by the rotation of the welding wire feeding roll 5 coupled to the welding wire feeding motor WM, and is fed from the power source main circuit PM through a feeding chip (not shown). Electric power is supplied, and an arc 3 is generated between the base material 2 and the base material 2. The filler wire 6 is fed through the filler wire guide 7 by the rotation of the filler wire feed roll 8 coupled to the filler wire feed motor FM, and is inserted into the molten pool formed by the arc 3. The weaving signal generation circuit WS outputs a weaving signal Ws that is a sine wave. Here, Ws = sin (2 · π · f · t), f is a predetermined weaving frequency, and t is an elapsed time. The weaving driving mechanism 9 is a mechanism including a motor for weaving the filler wire 6 in the front-rear direction of the welding direction with the weaving signal Ws as an input. Conventionally, a mechanism for converting the rotational motion of the motor into a linear motion by a slider crank mechanism, a mechanism for converting the rotational motion of the motor into a swinging motion by a crank and a swing rod, and the like are used. The weaving drive mechanism 9 changes the displacement amount Lh at the insertion position of the filler wire 6 as expressed by the above-described equation (1). The amplitude Sw is set by the weaving drive mechanism 9.

  The voltage detection circuit VD detects the welding voltage Vw and outputs a voltage detection signal Vd. The voltage smoothing circuit VAV receives the voltage detection signal Vd as an input, averages it (passes through a low-pass filter having a cutoff frequency of about 1 to 10 Hz), and outputs a welding voltage average value signal Vav. The voltage setting circuit VR outputs a predetermined welding voltage setting signal Vr. The voltage error amplification circuit EV amplifies an error between the welding voltage setting signal Vr and the welding voltage average value signal Vav, and outputs a voltage error amplification signal Ev.

  The voltage / frequency conversion circuit VF converts the signal into a signal having a frequency proportional to the value of the voltage error amplification signal Ev, and outputs a pulse period signal Tf having a high level for a short time at each frequency (pulse period). The frequency modulation control described above is performed by this voltage / frequency conversion circuit VF. The peak period setting circuit TPR outputs a predetermined peak period setting signal Tpr. The peak period timer circuit TP receives the pulse period signal Tf and the peak period setting signal Tpr as described above, and becomes the High level only for a period determined by the peak period setting signal Tpr from the time when the pulse period signal Tf changes to the High level. The peak period signal Tp is output. Therefore, the peak period signal Tp is a signal whose period is a pulse period, which is at a high level during the peak period and at a low level during the base period.

  The peak current setting circuit IPR outputs a predetermined peak current setting signal Ipr. The base current setting circuit IBR outputs a predetermined base current setting signal Ibr. The current control setting circuit ICR receives the peak period signal Tp, the peak current setting signal Ipr, and the base current setting signal Ibr, and sets the peak current when the peak period signal Tp is at a high level (peak period). The signal Ipr is output as the current control setting signal Icr, and the base current setting signal Ibr is output as the current control setting signal Icr in the low level (base period). The current detection circuit ID detects the welding current Iw and outputs a current detection signal Id. The current error amplification circuit EI amplifies an error between the current control setting signal Icr and the current detection signal Id, and outputs a current error amplification signal Ei. The drive circuit DV receives the current error amplification signal Ei, performs PWM modulation control based on this signal, and based on the result, outputs a drive signal Dv for driving the inverter circuit in the power supply main circuit PM. Output.

  The welding wire feed speed setting circuit WR outputs a predetermined welding wire feed speed setting signal Wr. The welding wire feed control circuit WC supplies the welding wire feed control signal Wc for feeding the welding wire 1 at a feed speed corresponding to the value of the welding wire feed speed setting signal Wr. Output to motor WM. The amplitude center feeding speed setting circuit FWCR outputs a predetermined amplitude center feeding speed setting signal Fwcr. The feed speed amplitude setting circuit SFR outputs a predetermined feed speed amplitude setting signal Sfr. The filler wire feed speed setting circuit FR receives the above-described amplitude center feed speed setting signal Fwcr and the feed speed amplitude setting signal Sfr as input, and fills the filler wire that changes into a limit wave shape based on the above-described equation (2). A feed speed setting signal Fr is output. Since the elapsed time t when generating the weaving signal Ws and the elapsed time t when generating the filler wire feed speed setting signal Fr are the same value, the two signals must be synchronized. become. As described above, equation (3) may be used instead of equation (2). Further, the expressions (41) and (42) may be used instead of the expression (2). The filler wire feed control circuit FCT sends a filler wire feed control signal Fct for feeding the filler wire 6 at a feed speed corresponding to the value of the filler wire feed speed setting signal Fr to the filler wire feed motor. Output to FM.

  According to the above-described embodiment, the insertion position of the filler wire is weaved in the front-rear direction of the welding direction, and the feeding speed of the filler wire is changed in synchronization with the weaving. As a result, when the filler wire insertion position is in the forward direction, the filler wire is accelerated to increase the average value of the filler wire feeding speed, and when it is in the rear direction, the molten pool is cooled and raised. It suppresses the formation of humping beads. As a result, in this embodiment, it becomes possible to perform high-weld welding and high-speed welding as compared with the prior art.

DESCRIPTION OF SYMBOLS 1 Welding wire 2 Base material 2a Weld pool 3 Arc 4 Welding torch 5 Welding wire feeding roll 6 Filler wire 7 Filler wire guide 8 Filler wire feeding roll 9 Weaving drive mechanism a Welding target position b0 Insertion reference position (weaving center position)
b1 foremost position b2 rearmost position DV drive circuit Dv drive signal EI current error amplification circuit Ei current error amplification signal EV voltage error amplification circuit Ev voltage error amplification signal f weaving frequency Fc steady filler wire feed speed FCT filler wire feed control circuit Fct Filler wire feed control signal FM Filler wire feed motor FR Filler wire feed speed setting circuit Fr Filler wire feed speed setting signal Fw Filler wire feed speed Fwc Amplitude center feed speed FWCR Amplitude center feed speed setting circuit Fwcr Amplitude center feed speed setting signal Iav Welding current average value Ib Base current IBR Base current setting circuit Ibr Base current setting signal ICR Current control setting circuit Icr Current control setting signal ID Current detection circuit Id Current detection signal Ip Peak current IPR Peak current Setting circuit Ipr Peak current Constant signal Iw welding current Lh filler wire displacement Lw wire distance PM main power source circuit SFR feed velocity amplitude setting circuit Sfr feed velocity amplitude of the insertion position setting signal Sw amplitude t elapsed time Tb based period Tf pulse cycle (signal)
TP Peak period timer circuit Tp Peak period (signal)
TPR Peak period setting circuit Tpr Peak period setting signal VAV Voltage smoothing circuit Vav Welding voltage average value (signal)
Vb Base voltage VD Voltage detection circuit Vd Voltage detection signal VF Voltage / frequency conversion circuit Vp Peak voltage VR Voltage setting circuit Vr Welding voltage setting signal Vw Welding voltage WC Welding wire feed control circuit Wc Welding wire feed control signal WM Welding wire feed Feed motor WR Welding wire feed speed setting circuit Wr Welding wire feed speed setting signal WS Weaving signal generation circuit Ws Weaving signal 遅 延 Delay time

Claims (4)

In the two-wire welding control method of generating an arc between the consumable electrode and the base material to form a molten pool and welding while inserting a filler wire into the latter half of the molten pool,
Weaving the insertion position of the filler wire in the front-rear direction of the welding direction, and changing the feeding speed of the filler wire in synchronization with the weaving,
A two-wire welding control method characterized by the above. The amount of displacement when the insertion position is displaced in the front direction from the center position of the weaving is a positive value, the amount of displacement when the insertion position is displaced in the rear direction is a negative value, and the filler wire To change the feed speed in proportion to the amount of displacement,
The two-wire welding control method according to claim 1. When changing the feeding speed of the filler wire in proportion to the amount of displacement, a predetermined delay time is provided between both signals.
The two-wire welding control method according to claim 2. Making the feeding speed of the filler wire when the insertion position is displaced in the front direction from the weaving center position faster than the feeding speed of the filler wire when displacing in the rear direction;
The two-wire welding control method according to claim 1.

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