Welding end control method for submerged arc welding

Abstract

To surely prevent occurrence of a sticking phenomenon between a tip of a welding wire and a molten pool when completing submerged arc welding.SOLUTION: In a welding end control method for submerged arc welding, a welding end signal St is input at time t1, welding wire feed speed Fw is transiently decelerated and stopped due to inertia from the time t1 to time t11, and welding is ended by controlling welding current Iw during an anti-stick period until welding is ended at time t3, where the anti-stick period is formed by a first anti-stick period from the time t1 to time t2 and a second anti-stick period from the time t2 to time t3, the weld current Iw is applied during the first anti-stick period, and application of the weld current Iw is stopped to set the welding wire feed speed Fw to reverse feeding speed during the second anti-stick period.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a method for controlling the end of submerged arc welding. [Background technology]

[0002] Submerged arc welding has been known for some time. In submerged arc welding, granular flux is spread on the base metal, a welding wire is fed into the flux, and an arc is generated between the tip of the welding wire and the base metal to perform welding. In submerged arc welding, a large current is passed through a large diameter welding wire, thereby enabling high efficiency welding of thick plates.

[0003] When submerged arc welding is terminated, if the welding current is stopped at the same time as a command to stop feeding the welding wire is issued, a stick phenomenon occurs in which the tip of the fed welding wire comes into contact with the molten pool due to inertia and becomes welded. To prevent this, in the invention of Patent Document 1, a welding end signal is input to the welding device, and the wire feeder decelerates transiently due to inertia and stops, and during the anti-stick period until welding is terminated, the welding current is supplied to terminate the welding. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2022-45137 Summary of the Invention [Problem to be solved by the invention]

[0005] In the conventional method of preventing the stick phenomenon by passing a welding current during the anti-stick period, the welding wire is so thick (diameter 2.4 mm or more) that melting is insufficient, and the stick phenomenon may occur depending on the welding conditions.

[0006] Therefore, an object of the present invention is to provide a method for controlling the end of submerged arc welding, which can reliably prevent the stick phenomenon from occurring. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the invention of claim 1 comprises: A method for controlling the end of submerged arc welding, in which a welding end signal is input to a welding device, a welding wire feeder is decelerated and stopped due to inertia, and during an anti-stick period until welding is ended, a welding current is controlled to end the welding, feeding the welding wire in reverse during at least a portion of the anti-stick period; The present invention relates to a method for controlling the end of submerged arc welding.

[0008] The invention of claim 2 is as follows: the anti-stick period is composed of a first anti-stick period and a second anti-stick period, the welding current is supplied during the first anti-stick period, and the supply of the welding current is stopped and the welding wire is fed in a reverse direction during the second anti-stick period. 2. The method for controlling the end of submerged arc welding according to claim 1,

[0009] The invention of claim 3 is as follows: during the anti-stick period, the welding current is applied and the welding wire is fed in reverse; 2. The method for controlling the end of submerged arc welding according to claim 1,

[0010] The invention of claim 4 is as follows: During the anti-stick period, the supply of the welding current is stopped and the welding wire is fed in reverse. 2. The method for controlling the end of submerged arc welding according to claim 1, Effect of the Invention

[0011] According to the method for controlling the end of submerged arc welding of the present invention, the occurrence of the stick phenomenon can be reliably prevented, and therefore a decrease in work efficiency can be suppressed. [Brief description of the drawings]

[0012] [Figure 1] 1 is a block diagram of a welding device for carrying out a method for controlling the end of submerged arc welding according to an embodiment of the present invention. [Diagram 2] FIG. 4 is a waveform diagram of a welding current Iw and a welding voltage Vw. [Diagram 3] 4 is a timing chart of each signal in the welding device of FIG. 1, illustrating a first welding end control according to the embodiment of the present invention. [Figure 4] 4 is a timing chart of each signal in the welding device of FIG. 1, illustrating second welding end control according to the embodiment of the present invention. [Diagram 5] 4 is a timing chart of each signal in the welding device of FIG. 1, illustrating a third welding end control according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0014] 1 is a block diagram of a welding device for carrying out a method for controlling the end of submerged arc welding according to an embodiment of the present invention. Each block will be described below with reference to the diagram.

[0015] The power supply main circuit PM is connected to a commercial power supply (not shown) such as a three-phase 200V power supply, and receives a drive signal Dv and a polarity switching signal Spn (described later) as inputs, performs inverter control according to the drive signal Dv, switches between electrode positive polarity EP and electrode negative polarity EN according to the polarity switching signal Spn, and outputs AC welding current Iw and welding voltage Vw. Although not shown, the power supply main circuit PM includes a primary rectifier that rectifies the commercial power supply, a smoothing capacitor that smoothes the rectified DC, a primary-side inverter circuit driven by the drive signal Dv to convert the smoothed DC into high-frequency AC, a high-frequency transformer that steps down the high-frequency AC to a voltage value suitable for welding, a secondary rectifier that rectifies the stepped-down high-frequency AC into DC, a reactor that smoothes the rectified DC, and a secondary-side inverter circuit that switches the smoothed DC between electrode positive polarity EP and electrode negative polarity EN according to the polarity switching signal Spn.

[0016] The welding wire 1 is fed through the welding torch 4 by the rotation of a feed roll 5 coupled to a feeder WM, and an arc 3 is generated between the welding wire 1 and the base material 2. A welding voltage Vw is applied between a power feed tip (not shown) of the welding torch 4 and the base material 2, and a welding current Iw flows. A flux feeder 6 supplies flux (not shown) to the arc generating part. The arc generating part is covered with the flux, so the arc 3 cannot be seen from the outside. The welding torch 4 is mounted on a cart, a robot, or the like, and moves along the weld line.

[0017] The welding start / end circuit ST outputs a welding start / end signal St which goes to a high level (welding start signal) when welding starts and a low level (welding end signal) when welding ends. For example, this circuit may be a switch or push button, and outputs a welding start / end signal St which goes to a high level when turned on and a low level when turned off. When a welding robot (not shown) is used, the welding start / end signal St is output from the robot control device (not shown).

[0018] The anti-stick period circuit SA receives the above-mentioned welding start / end signal St as an input, and outputs an anti-stick period signal Sa which is at a high level for a predetermined anti-stick period Ta from the time when the welding start / end signal St changes from a high level (welding start signal) to a low level (welding end signal). This circuit sets the anti-stick period Ta from when the welding end signal is input to the welding equipment and the feeder WM of the welding wire 1 decelerates transiently due to inertia and stops, until the welding is ended.

[0019] The steady-state current effective value setting circuit ICR outputs a steady-state current effective value setting signal Icr during a predetermined steady-state welding period. The anti-stick current effective value setting circuit IAR outputs an anti-stick current effective value setting signal Iar during a predetermined anti-stick period Ta. The current effective value setting circuit IER receives the anti-stick period signal Sa, the steady-state current effective value setting signal Icr, and the anti-stick current effective value setting signal Iar as inputs, and outputs the steady-state current effective value setting signal Icr as the current effective value setting signal Ier when the anti-stick period signal Sa is at a low level (steady welding period), and outputs the anti-stick current effective value setting signal Iar as the current effective value setting signal Ier when the anti-stick period signal Sa is at a high level (anti-stick period Ta).

[0020] The current detection circuit ID detects the instantaneous value of the AC welding current Iw, converts it into an absolute value, and outputs a current detection signal Id.

[0021] The current effective value detection circuit IED receives the current detection signal Id, calculates an effective value from the current detection signal Id, and outputs a current effective value detection signal Ied.

[0022] The current amplitude modulation circuit AMC receives the RMS current detection signal Ied and the RMS current setting signal Ier, performs modulation control based on the error amplification value between the two signals, and outputs a current amplitude modulation signal Amc. This circuit changes the amplitude of the welding current Iw so that the RMS current value becomes equal to the set value.

[0023] The electrode positive polarity period setting circuit TPR outputs a predetermined electrode positive polarity period setting signal Tpr, and the electrode negative polarity period setting circuit TNR outputs a predetermined electrode negative polarity period setting signal Tnr.

[0024] The current setting circuit IR receives the electrode positive polarity period setting signal Tpr, the electrode negative polarity period setting signal Tnr, and the current amplitude modulation signal Amc as inputs, performs the following processes 1) to 3), and outputs a current setting signal Ir having a half-sine waveform, as well as a polarity switching signal Spn for switching the power supply polarity. 1) During the electrode positive polarity period Tep set by the electrode positive polarity period setting signal Tpr, the start and end points of the period become the polarity switching current value, and a half-wave sine wave having an amplitude set by the current amplitude modulation signal Amc is output as the current setting signal Ir. During the electrode positive polarity period Tep, a polarity switching signal Spn that is at a High level is output. 2) During the electrode negative polarity period Ten set by the electrode negative polarity period setting signal Tnr, the start and end points of the period are the polarity switching current value, and a half-sine wave waveform with an amplitude set by the current amplitude modulation signal Amc is output as the current setting signal Ir. During the electrode negative polarity period Ten, a polarity switching signal Spn that is at a low level is output. 3) Repeat steps 1) and 2) above.

[0025] The current error amplifier circuit EI receives the current setting signal Ir and the current detection signal Id, amplifies the error between the two values, and outputs a current error amplified signal Ei. This circuit controls the welding device to have a constant current.

[0026] The welding end control selection circuit SE outputs a welding end control selection signal Se=1 when the first welding end control is selected, outputs a welding end control selection signal Se=2 when the second welding end control is selected, and outputs a welding end control selection signal Se=3 when the third welding end control is selected. This circuit is a switch, a touch panel, or the like, and the welding operator selects one of the first to third welding end controls.

[0027] The drive circuit DV receives the above-mentioned welding start / end signal St, the above-mentioned anti-stick period signal Sa, the above-mentioned current error amplified signal Ei, and the above-mentioned welding end control selection signal Se as inputs, performs the following processing, and outputs a drive signal Dv. 1) When the welding end control selection signal Se=1 (first welding end control) During the period from when the welding start / end signal St changes to high level until the anti-stick period signal Sa changes to high level and a predetermined first anti-stick period has elapsed, modulation control is performed based on the current error amplified signal Ei, and a drive signal Dv for driving the primary side inverter circuit in the power supply main circuit Pm is output. Then, during the second anti-stick period from when the first anti-stick period ends until the anti-stick period signal Sa changes to low level, the drive signal Dv is not output. With this control, the welding current Iw flows during the steady welding period and the first anti-stick period. 2) When the welding end control selection signal Se=2 (second welding end control) During the period from when the welding start / end signal St changes to high level to when the anti-stick period signal Sa changes to low level, modulation control is performed based on the current error amplified signal Ei and a drive signal Dv is output to drive the primary side inverter circuit in the power supply main circuit Pm. Due to this control, the welding current Iw flows during the steady welding period and the anti-stick period Ta. 3) When the welding end control selection signal Se=3 (third welding end control) During the steady welding period when the welding start / end signal St is at a high level, modulation control is performed based on the current error amplified signal Ei, and a drive signal Dv is output to drive the primary inverter circuit in the power supply main circuit Pm. Due to this control, the welding current Iw flows during the steady welding period, but does not flow during the anti-stick period Ta.

[0028] The voltage detection circuit VD detects the effective value of the AC welding voltage Vw and outputs a voltage detection signal Vd. The voltage detection signal Vd is a value that correlates with the arc length, so it detects the arc length. The voltage setting circuit VR outputs a predetermined voltage setting signal Vr for setting the desired arc length.

[0029] The variable feed speed control circuit FMC receives the voltage detection signal Vd and the voltage setting signal Vr, performs the variable feed speed control shown below based on the error between these two values, and outputs a feed speed modulation signal Fmc. 1) The variable feed speed control changes the value of the feed speed modulation signal Fmc based on the error by increasing (accelerating), decreasing (decelerating) or decreasing it to a negative value (reverse feed speed). 2) Preferably, the variable feed speed control varies the value of the feed speed modulation signal Fmc, including decreasing it to a negative value (reverse feed speed), when the voltage detection signal Vd is smaller than the voltage setting signal Vr. 3) More preferably, the variable feed speed control reduces the value of the feed speed modulation signal Fmc to a negative value (reverse feed speed) when the absolute value of the error is equal to or greater than a reference value when the voltage detection signal Vd is smaller than the voltage setting signal Vr.

[0030] The feed control circuit FC receives the above-mentioned feed speed modulation signal Fmc and the above-mentioned welding end control selection signal Se as inputs, performs the following processing, and outputs a feed control signal Fc. 1) When the welding end control selection signal Se=1 (first welding end control) During the period from when the welding start / end signal St changes to a high level until the anti-stick period signal Sa changes to a high level and a predetermined first anti-stick period has elapsed, the feeding speed Fw of the welding wire 1 is controlled to a speed determined by the feeding speed modulation signal Fmc. Then, during a second anti-stick period from when the first anti-stick period ends until the anti-stick period signal Sa changes to a low level, the welding wire 1 is fed backward at a predetermined reverse feeding speed. With this control, variable feeding speed control is performed during the steady welding period and the first anti-stick period, and the welding wire 1 is fed backward during the second anti-stick period. 2) When the welding end control selection signal Se=2 (second welding end control) and Se=3 (third welding end control) During the steady welding period when the welding start / end signal St is at a high level, the feed speed Fw of the welding wire 1 is controlled to a speed determined by the feed speed modulation signal Fmc. Then, during the anti-stick period Ta when the anti-stick period signal Sa is at a high level, the welding wire 1 is fed in reverse at a predetermined reverse feed speed. With this control, variable feed speed control is performed during the steady welding period, and the welding wire 1 is fed in reverse during the anti-stick period.

[0031] 2 is a waveform diagram of the welding current Iw and the welding voltage Vw. In the figure, positive values ​​above 0 A and 0 V correspond to the electrode positive polarity EP, and negative values ​​below 0 V correspond to the electrode negative polarity EN.

[0032] As shown in FIG. 1A, during an electrode positive polarity period Tep from time t1 to t2, the welding current Iw has a positive polarity switching current value at the start point t1 and end point t2 of the period, and has a positive half-wave waveform of a sine wave with an amplitude set by the current amplitude modulation signal Amc. As shown in FIG. 1A, during an electrode negative polarity period Ten from time t2 to t3, the welding current Iw has a negative polarity switching current value at the start point t2 and end point t3 of the period, and has a negative half-wave waveform of a sine wave with an amplitude set by the current amplitude modulation signal Amc. The electrode positive polarity period Tep is set by the electrode positive polarity period setting signal Tpr in FIG. 1. The electrode negative polarity period Ten is set by the electrode negative polarity period setting signal Tnr in FIG. 1. The amplitude is modulated and controlled so that the current effective value detection signal Ied in FIG. 1 is equal to the current effective value setting signal Ier. For example, Tep=10 ms, Ten=10 ms, polarity switching current value=±200A, and amplitude=±1000A.

[0033] As shown in Fig. 1B, the welding voltage Vw has a waveform similar to an AC square wave. The effective value of the welding voltage Vw is a value that correlates with the arc length.

[0034] Fig. 3 is a timing chart of each signal in the welding device of Fig. 1, showing the first welding end control according to an embodiment of the present invention. Fig. 3(A) shows the change over time of the welding start / end signal St, Fig. 3(B) shows the change over time of the anti-stick period signal Sa, Fig. 3(C) shows the change over time of the current effective value detection signal Ied, and Fig. 3(D) shows the change over time of the feed speed Fw. The operation of each signal will be explained below with reference to the figure.

[0035] This figure shows the case where the first welding end control is selected by the welding end control selection circuit SE in Figure 1, and the welding end control selection signal Se in Figure 1 becomes 1. In this figure, the period from time t0 to t1 is the steady welding period, the period from time t1 to t2 is the first anti-stick period, and the period from time t2 to t3 is the second anti-stick period.

[0036] (1) Operation during steady welding period from time t0 to t1 As shown in FIG. 1(A), the welding start / end signal St is a high-level welding start signal. As shown in FIG. 1(B), the anti-stick period signal Sa is a low-level signal. As shown in FIG. 1(C), the current effective value detection signal Ied is a constant value, and the amplitude of the welding current Iw in FIG. 2 is feedback-controlled so that it is equal to the value of the steady-state current effective value setting signal Icr in FIG. 1. As shown in FIG. 1(D), the feed speed Fw is a value that fluctuates up and down, and is variably controlled so that the value of the voltage detection signal Vd in FIG. 1, which correlates with the arc length, is equal to the value of the voltage setting signal Vr in FIG. 1. The average value of the feed speed Fw is a positive value, and the welding wire is forward-fed in a direction approaching the base metal, resulting in a positive feed state. The average value of the feed speed Fw during the steady-state welding period is, for example, 0.5 to 2 m / min.

[0037] (2) Operation in the first anti-stick period from time t1 to time t2 At time t1, as shown in FIG. 1A, the welding start / end signal St changes to a low level (welding end signal). In response to this, as shown in FIG. 1B, the anti-stick period signal Sa changes to a high level, and the predetermined first anti-stick period continues until time t2. As shown in FIG. 1C, the current effective value detection signal Ied is a constant value, and the amplitude of the welding current Iw in FIG. 2 is feedback-controlled so that it is equal to the value of the anti-stick current effective value setting signal Iar in FIG. 1. Here, the value of the anti-stick current effective value setting signal Iar is set to a value equal to or lower than the steady-state current effective value setting signal Icr. As shown in FIG. 1D, the feed speed Fw is decelerated by inertia from time t1, becomes 0 at time t11, and feed stops. Therefore, feed stops in the middle of the first anti-stick period, and the welding current Iw continues to flow even after that. The tip of the welding wire is melted and flares up due to the flow of the welding current Iw, preventing it from coming into contact with the molten pool. For example, the inertial period from time t1 to t11 is 50 ms, and the first anti-stick period from time t1 to t2 is 200 ms.

[0038] (3) Operation in the second anti-stick period from time t2 to time t3 When the first anti-stick period ends at time t2, the second anti-stick period begins. As shown in FIG. 1C, the current effective value detection signal Ied becomes 0, and the flow of the welding current Iw is stopped. As shown in FIG. 1D, the feed speed Fw becomes a negative value, and the welding wire is fed backward at a predetermined reverse feed speed. Reverse feed means feeding the welding wire backward in a direction away from the base metal. This causes the tip of the welding wire to move further away from the molten pool, thereby reliably preventing the sticking phenomenon with the molten pool. For example, the second anti-stick period from time t2 to t3 is 200 ms, and the reverse feed speed is 1.2 m / min. In this case, the tip of the welding wire is raised by 4 mm due to reverse feed. The second anti-stick period and the reverse feed speed are set by the welding operator so that the tip position of the welding wire at the end of welding is appropriate.

[0039] Fig. 4 is a timing chart of each signal in the welding device of Fig. 1, showing the second welding end control according to an embodiment of the present invention. Fig. 4(A) shows the change over time of the welding start / end signal St, Fig. 4(B) shows the change over time of the anti-stick period signal Sa, Fig. 4(C) shows the change over time of the current effective value detection signal Ied, and Fig. 4(D) shows the change over time of the feed speed Fw. The operation of each signal will be explained below with reference to the figure.

[0040] This figure shows a case where the second welding end control is selected by the welding end control selection circuit SE in Figure 1, and the welding end control selection signal Se in Figure 1 becomes 2. In this figure, the period from time t0 to t1 is the steady welding period, and the period from time t1 to t2 is the anti-stick period Ta.

[0041] (1) Operation during steady welding period from time t0 to t1 The operation during this period is the same as that shown in FIG. 3 above, and therefore will not be described repeatedly.

[0042] (2) Operation during the anti-stick period from time t1 to t2 At time t1, as shown in FIG. 1A, the welding start / end signal St changes to a low level (welding end signal). In response to this, as shown in FIG. 1B, the anti-stick period signal Sa changes to a high level, and the anti-stick period continues until time t2. As shown in FIG. 1C, the current effective value detection signal Ied is a constant value, and the amplitude of the welding current Iw in FIG. 2 is feedback-controlled so as to be equal to the value of the anti-stick current effective value setting signal Iar in FIG. 1. As shown in FIG. 1D, the feed speed Fw changes to a negative value from time t1, and the welding wire is fed backward at a predetermined reverse feed speed. Therefore, during the anti-stick period Ta, the welding current Iw is passed and the welding wire is fed backward at the same time. The welding current Iw melts the tip of the welding wire and burns up, preventing it from coming into contact with the molten pool. In addition, since the tip of the welding wire is fed in reverse, the tip of the welding wire is sufficiently separated from the molten pool at the end of welding, and the stick phenomenon can be reliably prevented. For example, the anti-stick period Ta is 200 ms and the reverse feed speed is 1.2 m / min. In this case, the tip of the welding wire is raised by 4 mm due to the reverse feed in addition to the burning distance caused by the passage of the welding current Iw.

[0043] Fig. 5 is a timing chart of each signal in the welding device of Fig. 1, showing the third welding end control according to an embodiment of the present invention. Fig. 5(A) shows the change over time of the welding start / end signal St, Fig. 5(B) shows the change over time of the anti-stick period signal Sa, Fig. 5(C) shows the change over time of the current effective value detection signal Ied, and Fig. 5(D) shows the change over time of the feed speed Fw. The operation of each signal will be explained below with reference to the figures.

[0044] This figure shows a case where the third welding end control is selected by the welding end control selection circuit SE in Figure 1, and the welding end control selection signal Se in Figure 1 becomes 3. In this figure, the period from time t0 to t1 is the steady welding period, and the period from time t1 to t2 is the anti-stick period Ta.

[0045] (1) Operation during steady welding period from time t0 to t1 The operation during this period is the same as that shown in FIG. 3 above, and therefore will not be described repeatedly.

[0046] (2) Operation during the anti-stick period from time t1 to t2 At time t1, as shown in FIG. 1A, the welding start / end signal St changes to a low level (welding end signal). In response to this, as shown in FIG. 1B, the anti-stick period signal Sa changes to a high level, and the anti-stick period continues until time t2. As shown in FIG. 1C, the current effective value detection signal Ied becomes 0 A at time t1, and the flow of the welding current Iw stops. As shown in FIG. 1D, the feed speed Fw changes to a negative value from time t1, and the welding wire is fed backward at a predetermined reverse feed speed. Therefore, during the anti-stick period Ta, the flow of the welding current Iw is stopped, and the welding wire is fed backward. Since the welding wire is fed backward during the anti-stick period Ta, even if the welding wire is not melted by the flow of the welding current Iw, the tip of the welding wire is sufficiently separated from the molten pool at the end of welding, and the stick phenomenon can be reliably prevented. For example, when the anti-stick period Ta is 300 ms and the reverse feed speed is 1.2 m / min, the tip of the welding wire is pulled up by 6 mm by reverse feed.

[0047] The effects of this embodiment will be described below. According to this embodiment, in the method for controlling the end of submerged arc welding, the welding wire is fed in the reverse direction during at least a portion of the anti-stick period. In the conventional method of preventing the stick phenomenon by passing a welding current during the anti-stick period, the welding wire has a large diameter and is not melted sufficiently, which may cause the stick phenomenon depending on the welding conditions. In this embodiment, by feeding the welding wire in the reverse direction during at least a portion of the anti-stick period, the tip of the welding wire can be sufficiently separated from the molten pool, thereby reliably preventing the stick phenomenon from occurring.

[0048] More preferably, according to this embodiment, the anti-stick period is formed of a first anti-stick period and a second anti-stick period, and during the first anti-stick period, the welding current is applied, and during the second anti-stick period, the application of the welding current is stopped and the welding wire is fed in the reverse direction. During the first anti-stick period, the tip of the welding wire is melted and flared up by the application of the welding current, and is moved away from the molten pool. During the subsequent second anti-stick period, the welding wire is fed in the reverse direction to increase the distance away from the molten pool. As a result, in this embodiment, the stick phenomenon can be reliably prevented.

[0049] More preferably, according to this embodiment, during the anti-stick period, the welding current is applied and the welding wire is fed in the reverse direction. The tip of the welding wire is melted and flared up by the application of the welding current. In addition, the tip of the welding wire is moved away from the molten pool by the reverse feeding of the welding wire. These two actions in this embodiment can reliably prevent the stick phenomenon from occurring.

[0050] More preferably, according to this embodiment, during the anti-stick period, the flow of the welding current is stopped and the welding wire is fed in the reverse direction. Even if the tip of the welding wire is not melted by the flow of the welding current, the tip of the welding wire can be moved away from the molten pool by feeding the welding wire in the reverse direction. As a result, this embodiment can reliably prevent the stick phenomenon from occurring. [Explanation of symbols]

[0051] 1 Welding wire 2 Base material 3. Arc 4. Welding torch 5 Feeding roll 6 Flux supply machine AMC Current Amplitude Modulation Circuit Amc Current Amplitude Modulation Signal DV driver circuit Dv drive signal EI Current Error Amplifier Circuit Ei Current error amplification signal EN Electrode negative polarity EP electrode positive polarity FC feed control circuit Fc feed control signal FMC Variable speed feed control circuit Fmc Feed speed modulation signal Fw Feeding speed IAR Anti-stick current effective value setting circuit Iar Anti-stick current effective value setting signal ICR Constant current effective value setting circuit Icr Steady-state current effective value setting signal ID Current Detection Circuit Id Current detection signal IED Current Effective Value Detection Circuit Ied Current effective value detection signal IER Current effective value setting circuit Ier Current effective value setting signal IR current setting circuit Ir Current setting signal Iw Welding current PM power supply main circuit SA Anti-stick period circuit Sa Anti-stick period signal SE Welding end control selection circuit Se Welding end control selection signal SPN polarity switching signal ST Welding start / end circuit St Welding start / end signal Ten electrode negative polarity period Tep electrode positive polarity period TNR Electrode negative polarity period setting circuit Tnr Electrode negative polarity period setting signal TPR electrode positive polarity period setting circuit Tpr electrode positive polarity period setting signal VD voltage detection circuit Vd Voltage detection signal VR voltage setting circuit Vr Voltage setting signal Vw welding voltage WM feeder

Claims

1. A method for controlling the end of submerged arc welding, in which a welding end signal is input to a welding device, a welding wire feeder is decelerated and stopped due to inertia, and during an anti-stick period until welding is ended, a welding current is controlled to end the welding, feeding the welding wire in reverse during at least a portion of the anti-stick period; A method for controlling the end of submerged arc welding.

2. the anti-stick period is composed of a first anti-stick period and a second anti-stick period, the welding current is supplied during the first anti-stick period, and the supply of the welding current is stopped and the welding wire is fed in a reverse direction during the second anti-stick period.

2. The method for controlling the end of submerged arc welding according to claim 1.

3. during the anti-stick period, the welding current is applied and the welding wire is fed in reverse; 2. The method for controlling the end of submerged arc welding according to claim 1.

4. During the anti-stick period, the supply of the welding current is stopped and the welding wire is fed in reverse.

2. The method for controlling the end of submerged arc welding according to claim 1.

Images