JP2015030017A - Arc welding control method, and arc welding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that in an arc welding control method for causing a welding droplet at a wire leading end to contact with a molten pool into a short circuit for a falling period or base current period, for which the peak current of a pulse waveform transfers into a base current, in the case of welding a galvanized steel plate is welded, because the vibration of a molten pool is so relatively small that zinc vapor hardly passes through the molten pond (or the molten metal) and hardly diffuses to the outside thereby to form blow holes in a welding bead and on the surface of the weld beads.SOLUTION: In a welding operation of a steel sheet having been subjected to a surface treatment of a galvanized steel plate and the like, a one-pulse/one-short circuiting transfer is performed for a peak current period of a pulse welding. As a result, a molten pool (or a molten metal) on the steel plate can be highly vibrated so that the zinc vapor produced from the steel sheet passes through the molten pool (or the molten metal) and easily volatilizes to the outside thereby to suppress blow holes which might otherwise be formed in or on the surface of the welding bead.

Description

  The present invention relates to an arc welding control method and a welding apparatus that are effective in reducing blowholes and pits in pulse welding of a surface-treated member such as a galvanized steel sheet.

  Galvanized steel sheets are excellent in rust prevention and corrosion resistance. Therefore, in recent years, it is used for automobile parts, building steel members, and the like, and the demand is increasing year by year.

  However, there are problems with the use of galvanized steel sheets. Zinc plated on the surface of a galvanized steel sheet has a lower melting point than iron. Therefore, when a galvanized steel sheet is welded, the zinc is vaporized, and zinc vapor passes through the molten pool and the molten metal and tends to diffuse outside. However, when solidification of the molten metal is fast, zinc vapor cannot be diffused to the outside and remains as blow holes or pits (hereinafter referred to as pores) in the weld bead or on the weld bead surface. Such pores can also lead to serious weld defects.

  The following are known as conventional pulse welding control methods (see, for example, Patent Document 1). A short circuit has occurred at time 108 within the second basic pulse period 101 shown in FIG. When a short circuit occurs, short circuit control is started to output a current with a slope smaller than the rising speed of the pulse current.

  As shown in FIG. 7, a short circuit is also occurring at a time point 106 that is the end point of the second basic pulse period 101. Therefore, short circuit control is continued. After that, when the secondary side control unit detects the necking phenomenon immediately before the short circuit is released based on the output of the welding voltage value detection unit, etc., the secondary side control unit controls when the necking is detected with respect to the drive unit. A signal indicating that the operation is to be performed is output. The drive unit that receives this signal outputs a signal to the secondary side switching element, and turns off the switching element (non-conduction). And when this switching element becomes non-conductive, the energy in a welding energization path will be consumed by resistance. As a result, the welding current is sharply reduced as shown at time 107 in FIG. This constriction control is widely known from the past.

  Even if the welding current is reduced during constriction, the molten wire is transferred to the base material by the pinch force. Therefore, it hardly affects the release of the short circuit.

  As described above, when a short circuit occurs during pulse welding, in order to open this short circuit, a welding current having a slope smaller than the slope at the rising edge of the current waveform of the pulse current is energized, and the short circuit caused by this energization. Necking is detected during release, and the welding current value is sharply reduced. Therefore, it is possible to reduce the influence of the welding current relating to the occurrence of spatter when the short circuit is opened, and as a result, it is possible to reduce the amount of spatter generated when the short circuit is opened.

JP 2006-334601 A

  Conventionally, in pulse welding, the welding voltage must be set low during high-speed welding. The reason is that the welding voltage is set low in order to suppress undercutting and humping, and a short circuit is generated while welding is performed by pulse welding. However, if the welding voltage is low, the short circuit time (the time from the start of the short circuit to the opening of the short circuit) becomes long, and the current at the time of short circuit opening increases, so the spatter at the time of short circuit opening increases. However, in the conventional pulse welding control, the spatter can be reduced by sharply reducing the welding current when detecting the constriction phenomenon just before the short circuit is opened.

  However, when a galvanized steel sheet is welded by the conventional pulse welding control described above, zinc vapor cannot pass through the molten pool (molten metal) and diffuse to the outside. As a problem. The reason will be described below.

  In conventional pulse welding control, droplets are formed at the tip of the wire during the peak current period of the pulse waveform, and the droplet at the tip of the wire contacts the molten pool during the falling or base current period when the peak current changes to the base current. Thus, a short circuit transition is performed. Although a short circuit occurs during the fall period or base current period when the peak current shifts to the base current, the current before the short circuit is low, so the oscillation of the molten pool is relatively small, and the zinc vapor flows into the molten pool (molten metal). ) And hardly diffuses to the outside, so that pores are likely to remain.

  According to the present invention, the 1 pulse / 1 short circuit transition is generated not at the falling period or the base current period in which the current peak current shifts to the base current but at the peak current period. Because the current before the occurrence of a short circuit is high, the vibration of the molten pool (molten metal) is large and the zinc vapor easily passes through the molten pool (molten metal) and diffuses to the outside. An object of the present invention is to provide an arc welding control method and an arc welding apparatus for welding a steel plate that has been surface-treated such as a galvanized steel plate.

  In order to solve the above problems, an arc welding control method of the present invention is an arc welding control method for repeatedly supplying a peak current and a base current between a welding wire and a base material, and supplying the peak current. In each peak current period, a short circuit between the welding wire and the base material is generated each time.

  In addition to the above, the arc welding control method of the present invention controls the welding current waveform including the peak current and the base current so that the welding wire and the base material are short-circuited each time during the peak current period. It is.

  In addition to the above, the arc welding control method of the present invention controls the feeding speed of the welding wire so that the welding wire and the base material are short-circuited each time during the peak current period.

  In addition to the above, the arc welding control method of the present invention is configured such that the welding wire feeding speed during the peak current period is higher than the welding wire feeding speed during the base current period during which the base current is supplied. To control.

  Moreover, in addition to the above, the arc welding control method of the present invention uses a steel plate subjected to surface treatment as a base material.

  In addition to the above, the arc welding apparatus of the present invention is an arc welding apparatus that repeatedly supplies a peak current and a base current between a welding wire and a base material, the switching unit for controlling the welding current, A setting unit for setting a parameter related to the welding current, and a drive unit for controlling the switching unit based on the output of the setting unit, the drive unit, in the peak current period supplying the peak current every time, The welding current waveform including the peak current and the base current is controlled so that a short circuit between the welding wire and the base material occurs.

  The arc welding apparatus of the present invention is an arc welding apparatus that repeatedly supplies a peak current and a base current between a welding wire and a base material, and includes a switching unit that controls the welding current, and a parameter related to the welding current. A setting unit for setting, a drive unit for controlling the switching unit based on an output of the setting unit, and a feed rate control unit for controlling the feed rate of the welding wire, and the feed rate control unit includes: The welding wire feeding speed is controlled so that a short circuit between the welding wire and the base material occurs every time during the peak current period in which the peak current is supplied.

  The arc welding apparatus of the present invention is an arc welding apparatus that repeatedly supplies a peak current and a base current between a welding wire and a base material, and includes a switching unit that controls the welding current, and a parameter related to the welding current. A setting unit for setting, a drive unit for controlling the switching unit based on an output of the setting unit, and a feed rate control unit for controlling the feed rate of the welding wire, and supplying the peak current The drive unit controls the welding current waveform including the peak current and the base current so that a short circuit between the welding wire and the base material occurs every time during the peak current period, and the feeding speed The control unit controls the feeding speed of the welding wire.

  Further, in the arc welding apparatus of the present invention, in addition to the above, the feeding speed control unit feeds the welding wire feeding speed during the peak current period to the welding wire feeding during the base current period supplying the base current. It is controlled so as to be higher than the speed.

  In addition to the above, the arc welding apparatus of the present invention is a steel plate subjected to surface treatment as a base material.

  As described above, according to the present invention, in welding of a steel sheet subjected to surface treatment such as a galvanized steel sheet, the molten pool on the steel sheet is obtained by performing 1 pulse / 1 short-circuit transition during the peak current period of pulse welding. (Molten metal) can be vibrated greatly. Thereby, the vapor generated from the steel sheet easily passes through the molten pool (molten metal) and volatilizes to the outside, and the pores generated in the weld bead and the weld bead surface can be suppressed, thereby improving the weldability. it can.

The figure which shows schematic structure of the arc welding apparatus in Embodiment 1 of this invention. The figure which shows the waveform of the welding current in the Embodiment 1 of this invention, a welding voltage, and a wire feeding speed. (A) The figure which shows the welding state at the time of short circuit opening by a conventional construction method (b) The figure which shows the welding state at the time of short circuit opening in Embodiment 1 of this invention The figure which shows schematic structure of the arc welding apparatus in Embodiment 2 of this invention. The figure which shows the waveform of the welding current in the Embodiment 2 of this invention, a welding voltage, and a wire feeding speed. The figure which shows the effect of the wire feeding speed in Embodiment 2 of this invention. The figure which shows the welding current waveform in the conventional arc welding control

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

(Embodiment 1)
This embodiment will be described with reference to FIGS. FIG. 1 is a diagram showing a schematic configuration of an arc welding apparatus. FIG. 2 is a diagram illustrating waveforms of a welding current, a welding voltage, and a wire feeding speed. Fig.3 (a) is a figure which shows the welding state at the time of short circuit open | release by a conventional construction method. FIG.3 (b) is a figure which shows the welding state at the time of short circuit open | release in this Embodiment.

  In FIG. 1, the arc welding apparatus includes a welding power supply device 19, a robot 22, a robot control device 20 that controls the operation of the robot 22, a wire feeding unit 25, and the like.

  The welding power source device 19 includes a primary side rectification unit 2 that rectifies the output of the input power source 1, a switching unit 3 that controls the welding output by controlling the output of the primary side rectification unit 2, A transformer 4 that insulates and converts power; a secondary rectifier 5 that rectifies the secondary output of the transformer 4; and a reactor 6 (also referred to as DCL) connected in series to the secondary rectifier 5; A drive unit 7 for driving the switching unit 3, a welding voltage detection unit 8 for detecting a welding voltage, a welding current detection unit 9 for detecting a welding current, and an output of the welding voltage detection unit 8 and / or a welding current detection A short-circuit arc determination unit 10 that determines whether the welding state is a short-circuit state or an arc state based on the output of the unit 9, an arc control unit 11 that controls the drive unit 7 during the arc period, and a short-circuit period Short to control the drive unit 7 The control unit 15, the wire feed rate control unit 18 for controlling the wire feed rate according to the welding conditions, the pulse waveform parameter setting unit 17 for setting the waveform parameters for the short circuit period and the arc period, and the output terminal 30a And an output terminal 30b. The arc control unit 11 includes a peak current control unit 12 that performs pulse output during the arc period, a base current control unit 13, and a pulse current rising / falling control unit 14. The short circuit control unit 15 includes a short circuit current control unit 16.

  The pulse waveform parameter setting unit 17 has a table or a mathematical expression in which the wire feed speed and the waveform parameter are associated with each other, and the waveform parameter is set based on the wire feed speed output by the wire feed speed control unit 18. It has a function to determine.

  In the welding power supply device 19, when the arc control unit 11 receives a signal indicating an arc from the short-circuit arc determination unit 10 based on the output of the pulse waveform parameter setting unit 17, the peak current in the arc control unit 11 is received. The control unit 12 outputs the peak current IP. Thereafter, even when a signal indicating a short circuit is received from the short-circuit arc determination unit 10, the output of the peak current IP is continued during the short-circuit period. Thereafter, the constriction of the droplet at the tip of the wire starts while the peak current IP is output, and then the constricted state changes to the short-circuit open state (arc state). When the arc control unit 11 receives a signal indicating an arc from the short-circuit arc determination unit 10, the base current control unit 13 in the arc control unit 11 outputs the base current IB. In this way, pulse output control for alternately outputting the peak current and the base current is performed.

  The robot controller 20 that controls the operation of the robot 22 includes a welding condition setting unit 21 for storing welding conditions such as a set welding current set by a teaching pendant (not shown), for example. The robot controller 20 is communicably connected to the welding power source device 19 and transmits information stored in the welding condition setting unit 21 to the welding power source device 19. The robot 22 is provided with a torch 29 for arc welding.

  The wire feed speed control unit 18 provided in the welding power supply device 19 is based on the set welding current stored in the welding condition setting unit 21 provided in the robot control device 20 and corresponds to the set welding current. The feeding speed is determined, and this wire feeding speed WF is output. The pulse waveform parameter setting unit 17 receives the signal from the wire feed speed control unit 18 and sends it to the peak current control unit 12, the base current control unit 13, and the pulse current rise / fall control unit 14 in the arc control unit 11. The peak current IP and the base current IB corresponding to the received wire feed speed WF are alternately output. Further, the wire feeding unit 25 provided with the feeding roller feeds the welding wire 24 based on a signal from the wire feeding speed control unit 18.

  A welding condition setting unit 21 inside the robot control device 20 connected to the welding power source device 19 is for setting a welding current, a welding voltage, and the like.

  Of the two output terminals 30 a and 30 b provided in the welding power supply device 19, one output terminal 30 a is connected to the tip 26 that holds the welding wire 24 in the torch 29, and is connected via the tip 26. Then, electric power is supplied to the welding wire 24. The other output terminal 30 b is connected to the workpiece 28 and power is supplied to the workpiece 28. An arc 27 is generated between the tip of the welding wire 24 and the workpiece 28. The wire feeding unit 25 feeds the welding wire 24 from the welding wire storage unit 23 that stores the welding wire 24 toward the tip 26.

  The operation of the consumable electrode type arc welding apparatus configured as described above will be described. Note that the arc welding apparatus of the present embodiment suppresses pores generated when welding a steel sheet that has been surface-treated, such as a galvanized steel sheet, so that the welding wire 24 and the workpiece 28 are short-circuited. As described above, the welding current and the like are controlled. In other words, the steel wire is subjected to surface treatment by causing the welding wire 24 and the workpiece 28 to be short-circuited during the peak current period of pulse welding and opening the short-circuit during this peak current period to vibrate the molten pool actively. The generation of pores is suppressed by making it easy for the vapor generated from the steel plate when welding to pass through the molten pool (molten metal) and volatilize outside.

  In addition, in this Embodiment, the to-be-welded object 28 is a steel plate by which the surface treatment was performed, and demonstrates the case where a galvanized steel plate is used as the example.

  First, the control of 1 pulse / 1 short circuit transition by the arc control unit 11 and the short circuit control unit 15 will be described with reference to FIG. FIG. 2 is a diagram showing temporal changes in welding current A, welding voltage V, and wire feed speed WF during pulse welding of consumable electrode arc welding.

  In FIG. 2, the time point P1 is a time point when the arc control unit 11 starts rising from the base current IB to the peak current IP in the pulse current waveform. Time point P2 is a time point when the peak current IP is started. A period from the time point P1 to the time point P2 is defined as a pulse current rising period TPu. Time point P3 is a time point when the droplet formed on the tip portion of the welding wire 24 contacts the molten pool formed on the workpiece 28 and starts a short circuit during the peak current period of the pulse current waveform. The period from the time point P2 to the time point P3 is not set in advance, but changes according to the welding phenomenon that causes a short circuit state. The time point P4 is a time point during which the peak current IP is output even during the short circuit period, and the short circuit between the droplet formed on the tip of the welding wire 24 and the workpiece 28 is released while the output is continued. The period from the time point P3 to the time point P4 is not set in advance, but changes according to the welding phenomenon in which the short circuit is opened. Note that the period from the time point P2 to the time point P4 is a peak current period TP. This peak current period TP is not set in advance, but changes according to the welding phenomenon that results in a short circuit state and a short circuit open state.

  Incidentally, the short-circuit period from the time point P3 to the time point P4 has been described as an example of the peak current period TP, but the output control is performed so that the short-circuit current control unit 16 in the short-circuit control unit 15 gradually increases the slope of the short-circuit current. You may do it. If this method is used, the time to open the short circuit can be shortened, and the arc stability can be improved.

  Although the peak current IP is illustrated and described as a constant output, it may be controlled so as to gradually increase the peak current IP with a slope from the time point P2 to P3. According to this method, the detachability of the droplets is improved, the short circuit can be short-circuited at an early stage of the peak current period, and the certainty of the occurrence of the short circuit can be improved. The control may be performed so that the peak current IP is gradually increased from the time point P3 to the time point P4, which is the short circuit period. Therefore, the peak current IP may be controlled to gradually increase from the time point P2 to the time point P4.

  Time point P4 is a time point when the arc control unit 11 starts falling from the peak current IP to the base current IB. A period from the time point P4 to the time point P5 is defined as a pulse current falling period TPd.

  Further, this time point P5 is a time point when the base current IB is started. Time point P6 is a time point when the rising from the base current IB to the next peak current IP is started.

  A period from the time point P5 to the time point P6 is a base current period TB that is controlled to be the base current IB. For example, the base current period TB may be a predetermined period or a value corresponding to the pulse period PF.

  Since the peak current period TP changes according to the welding phenomenon that causes a short-circuit state, the time differs every time. Moreover, since the time of the short-circuit current period TS changes according to the welding phenomenon, the time is different each time. Therefore, as constant voltage control for controlling the output voltage to follow the voltage set by the welding operator, the base current period TB or the pulse period PF changes so as to be synchronized with the peak current period TP or the short-circuit current period TS. Will do. That is, when the pulse period PF is considered as constant control, the base current period TB is determined in real time according to the peak current period TP and the short circuit current period TS, and when the base current period TB is considered as constant control, the peak current period TP and short circuit are determined. The pulse period PF is determined in real time according to the current period TS, and constant voltage control is performed. Or you may make it change with both base current period TB and pulse period PF according to peak current period TP and short circuit current period TS.

  As described above, the period from the time point P1 to the time point P6 is the pulse cycle PF (one cycle). Note that the pulse waveform control similar to that from the time point P1 to the time point P6 is repeated from the time point P6 to the time point P10. The same applies to the time point P10 and thereafter.

  For the peak current, base current, base time, etc., values preset in the pulse waveform parameter setting unit 17 are used. This set value is stored in the pulse waveform parameter setting unit 17 by actually welding and extracting parameters suitable for the wire.

  In this pulse waveform control, the droplet transfer timing by 1 pulse / 1 short-circuit transfer is time point P3 when the short circuit is opened during the peak current period, and droplet formation at the wire tip is performed in the period from time point P4 to time point P7. Will be. Moreover, 1 pulse / 1 short circuit transition means that a short circuit occurs once by applying a current of a pulse of one cycle.

  Next, the effect of the peak current IP will be described below.

  The peak current IP is a peak current until a short circuit occurs during the peak current period. The peak current period is set by setting the peak current IP of the present embodiment higher than the normally used peak current with respect to the peak current used when welding a normal steel sheet that is not surface-treated. The short circuit is smoothly generated.

  In normal pulse waveform control for welding steel sheets that have not been surface-treated, droplets are formed at the wire tip during the peak current period of the pulse waveform and dropped during the falling or base current period when the peak current shifts to the base current. Alternatively, the peak current IP and the base current IB are determined so that one pulse / one droplet transfer can be realized so that the droplet at the tip of the wire comes into contact with the molten pool and is short-circuited.

  On the other hand, in the present embodiment, by setting the peak current IP higher than the peak current used in this normal steel plate, the formation of droplets can be accelerated and the droplet size can be increased. The aim is to generate a short circuit by making the droplets easily constricted and detached during the period.

  Although the reference value of the peak current IP depends on the wire classification and the wire component, it is possible to promote the occurrence of a short circuit during the peak current period by increasing the peak current by 20 A to 150 A higher than the peak current used in a normal steel plate. For example, when the peak current used in a normal steel plate is 400A to 500A and 1 pulse / drop is possible, the occurrence of a short circuit in the peak current period can be promoted by increasing the current from 500A to 600A. it can.

  Furthermore, by setting the setting voltage to be low so that the arc length becomes short, it is possible to reliably generate a short circuit during the peak current period.

  In addition, the peak current period TP is lengthened to accelerate the formation of the droplets and the droplet size is also increased, the droplets can be easily separated during the peak current period, and a short circuit can be generated by constriction. . However, if the peak current period becomes too long, the pulse period PF may become quite long (the pulse frequency is low). Therefore, the adjustment by the peak current value does not greatly change the pulse period PF, and the occurrence of a short circuit can be realized in the peak current period.

  In the present embodiment, a short circuit is generated during the peak current period. Therefore, the effect on the vibration of the molten pool is great, but the amount of sputtering increases. The amount of spatter generated is not always small. However, in order to solve the welding problem of pore defects such as blow holes and pits, the suppression of sputtering must be sacrificed to some extent. Since pores are more important than sputtering, it is important to suppress pores even at the expense of some sputtering.

  Next, the effect with respect to the vibration of the molten pool by the pulse welding control of this Embodiment is demonstrated using FIG. Fig.3 (a) is a figure which shows the welding state at the time of short circuit open | release by a conventional construction method. FIG.3 (b) is a figure which shows the welding state at the time of short circuit open | release in this Embodiment. FIG. 5 is an example of a photograph taken with a high-speed camera of the effect of the conventional pulse welding control at the time of short circuit opening of the welding current waveform (time point A) and the vibration of the weld pool by the pulse welding control of the present embodiment. .

  In conventional pulse welding control, droplets are formed at the tip of the wire during the peak current period of the pulse waveform, and the droplet at the tip of the wire contacts the molten pool during the falling or base current period when the peak current changes to the base current. To make a short-circuit transition. Therefore, as shown in the photograph of FIG. 3A, the molten pool has a relatively small vibration, so that the zinc vapor hardly passes through the molten pool (molten metal) and diffuses to the outside.

  In the pulse welding control of the present embodiment, the generation timing of 1 pulse / 1 short circuit transition is not the falling period or the base current period in which the peak current is shifted to the base current as in the prior art, but the peak current period. Control to generate 1 pulse / 1 short circuit transition. This increases the vibration of the molten pool (molten metal) when the short circuit is opened and pushes the molten metal in the molten pool to the outer periphery of the molten pool, so that the zinc vapor passes through the molten pool (molten metal). It becomes easy to diffuse outside.

  Thus, performing a 1 pulse / 1 short circuit transition during the peak current period of pulse welding is a welding method suitable for welding galvanized steel sheets.

  As described above, according to the arc welding control method and the arc welding apparatus of the present embodiment, the welding on the galvanized steel sheet is controlled by performing a 1 pulse / 1 short-circuit transition in the welding of the galvanized steel sheet. The pond (molten metal) can be vibrated greatly, zinc vapor can easily pass through the molten pond (molten metal) and volatilize to the outside, and welding should be performed with few pores in the weld bead or weld bead surface. And the generation of pores can be suppressed. In particular, since pits are likely to occur frequently during the arc start period, it is very effective during the arc start period.

  In this embodiment, a short circuit occurs during the peak current period by controlling the welding current waveform.

(Embodiment 2)
In the present embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. This embodiment will be described with reference to FIGS. FIG. 4 is a diagram showing a schematic configuration of the arc welding apparatus in the present embodiment. FIG. 6 is a diagram illustrating waveforms of a welding current, a welding voltage, and a wire feeding speed in the present embodiment. FIG. 6 is a diagram for explaining the effect of the wire feed speed in the present embodiment.

  The main difference from the first embodiment is that the pulse is a peak current IP having a magnitude different from that of the peak current used in a normal steel plate in order to reliably generate a 1 pulse / 1 short circuit transition during the peak current period. Instead of waveform control, the wire feeding speed WF is changed as a further effective method.

  The differences from the arc welding apparatus and the arc control method of the wire feed speed WF which is the constant feed described in the first embodiment are as follows. The wire feed speed control unit 18 that has received the signal at the time point P1 from the pulse current rising / falling control unit 14 sets the wire feed speed WF2 higher than the average wire feed speed WF1 with respect to the average wire feed speed WF1. increase. Thereafter, when the wire feeding speed control unit 18 receives a signal indicating a short circuit from the short-circuit arc determination unit 10, the average wire feeding speed WF1 from the point P3 in the peak current period TP to the point P6 in the base current period TB. To a lower wire feed speed WF3.

  Note that an average value of the wire feed speed WF2 higher than the average wire feed speed WF1 and the wire feed speed WF3 lower than the average wire feed speed WF1 is the average wire feed speed WF1.

  At the time point P1 when the pulse current rise starts, the pulse current rise / fall control unit 14 increases the wire feed speed WF2 higher than the average wire feed speed WF1 with respect to the average wire feed speed WF1, and determines a short circuit arc. An instruction is given to the wire feed speed controller 18 so as to maintain the wire feed speed WF2 until the time point P3 of the peak current period TP that receives a signal indicating a short circuit from the section 10.

  When the pulse current rising / falling control unit 14 receives a signal indicating a short circuit from the short-circuit arc determination unit 10 at the time point P3 during the peak current period TP, the wire feeding lower than the average wire feeding speed WF1. An instruction is given to the wire feed speed controller 18 so as to maintain the wire feed speed WF3 until the speed is reduced to the speed WF3 and until the time point P6 of the base current period TB.

  In this way, between the time point P3 of the peak current period TP and the time point P6 of the base current period TB, the short circuit is regulated in the peak current period by decelerating to the wire feed speed WF3 lower than the average wire feed speed WF1. Can be induced to prevent a short circuit from occurring in the base current period TB.

  With this method, it is possible to reliably and regularly generate a short circuit in the peak current period, rather than controlling with a pulse waveform. Therefore, the vibration of the molten pool can be increased and zinc vapor can be discharged smoothly.

  Here, the effect of the wire feeding speed in the present embodiment will be described with reference to FIG. FIG. 6 is a table when an appropriate amount of increase in the wire feed speed is evaluated by changing the wire feed speed WF2 higher than the average wire feed speed WF1.

  It represents whether or not a short circuit occurs during the peak current period when the average wire feed speed WF1 is increased every 5%. A case where a short circuit occurs during the peak current period is indicated by “◯”, and a case where a short circuit does not occur during the peak current period is indicated by “x”.

  When the average wire feed speed WF1 is increased by 5% or less, a short circuit cannot be generated in the peak current period. Moreover, if it is 30% or more, a short circuit can be generated in the peak current period, but the short circuit is too strong, so that the arc stability cannot be maintained.

  Therefore, the region from 10% to 25% is appropriate. This result is an example of welding with a welding current of 250A.

  As described above, according to the arc welding control method and the arc welding apparatus of the present embodiment, in the welding of the galvanized steel sheet, the wire feed speed is controlled so as to perform the 1 pulse / 1 short circuit transition, thereby making the zinc The molten pool (molten metal) on the plated steel plate can be vibrated greatly, the zinc vapor easily passes through the molten pool (molten metal) and volatilizes to the outside, and there are few pores in the weld bead or on the weld bead surface. Can be welded, and the generation of pores can be suppressed. In particular, since pits are likely to occur frequently during the arc start period, it is very effective during the arc start period.

  In the first embodiment, the welding current waveform including the peak current and the base current is controlled to short-circuit the welding wire 24 and the workpiece 28 during the peak current period every time. Moreover, in Embodiment 2, the example which short-circuits the welding wire 24 and the to-be-welded object 28 in the peak electric current period every time by controlling wire feeding speed was shown. Here, by performing both the control of the welding current waveform including the peak current and the base current and the control of the wire feed speed, the welding wire 24 and the workpiece 28 are short-circuited each time during the peak current period. You may do it.

  As described above, according to the present invention, in the welding of galvanized steel sheets by pulse welding, zinc vapor easily passes through the molten pool (molten metal) and volatilizes to the outside, and the generation of pores can be suppressed. The present invention is industrially useful as an arc welding control method and an arc welding apparatus for welding a surface-treated member.

DESCRIPTION OF SYMBOLS 1 Input power supply 2 Primary side rectification part 3 Switching part 4 Transformer 5 Secondary side rectification part 6 Reactor 7 Drive part 8 Welding voltage detection part 9 Welding current detection part 10 Short-circuit arc determination part 11 Arc control part 12 Peak current control part 13 Base current control unit 14 Pulse current rise / fall control unit 15 Short circuit control unit 16 Short circuit current control unit 17 Pulse waveform parameter setting unit 18 Wire feed speed control unit 19 Welding power supply device 20 Robot control device 21 Welding condition setting unit 22 Robot 23 Welding wire storage unit 24 Welding wire 25 Wire feeding unit 26 Tip 27 Arc 28 Workpiece 29 Torch 30a, 30b Output terminal

Claims (10)

An arc welding control method for repeatedly supplying a peak current and a base current between a welding wire and a base material,
An arc welding control method for generating a short circuit between the welding wire and the base material every time during a peak current period in which the peak current is supplied. The arc welding control method according to claim 1, wherein the welding current waveform including the peak current and the base current is controlled so that the welding wire and the base material are short-circuited each time during the peak current period. 3. The arc welding control method according to claim 1, wherein the feed rate of the welding wire is controlled so that the welding wire and the base material are short-circuited each time during the peak current period. The arc welding control method according to claim 3, wherein the feeding speed of the welding wire during the peak current period is controlled to be higher than the feeding speed of the welding wire during the base current period during which the base current is supplied. The arc welding control method according to any one of claims 1 to 4, wherein the base material is a steel plate that has been subjected to a surface treatment. An arc welding apparatus that repeatedly supplies a peak current and a base current between a welding wire and a base material,
A switching unit for controlling the welding current;
A setting unit for setting a parameter relating to the welding current;
A drive unit for controlling the switching unit based on the output of the setting unit;
The driving unit controls a welding current waveform including the peak current and the base current so that a short circuit occurs between the welding wire and the base material every time during a peak current period in which the peak current is supplied. Arc welding equipment to do. An arc welding apparatus that repeatedly supplies a peak current and a base current between a welding wire and a base material,
A switching unit for controlling the welding current;
A setting unit for setting a parameter relating to the welding current;
A drive unit that controls the switching unit based on an output of the setting unit;
A feed speed control unit for controlling the feed speed of the welding wire;
The feeding speed control unit controls the feeding speed of the welding wire so that a short circuit occurs between the welding wire and the base material every time during the peak current period in which the peak current is supplied. Welding equipment. An arc welding apparatus that repeatedly supplies a peak current and a base current between a welding wire and a base material,
A switching unit for controlling the welding current;
A setting unit for setting a parameter relating to the welding current;
A drive unit that controls the switching unit based on an output of the setting unit;
A feed speed control unit for controlling the feed speed of the welding wire;
The drive unit controls the welding current waveform including the peak current and the base current so that a short circuit between the welding wire and the base material occurs every time during the peak current period in which the peak current is supplied. And the feeding speed control unit controls the feeding speed of the welding wire. The feed rate control unit controls the feed rate of the welding wire during the peak current period to be higher than the feed rate of the welding wire during the base current period during which the base current is supplied. Arc welding equipment. The arc welding apparatus according to any one of claims 6 to 9, wherein the base material is a steel plate subjected to surface treatment.

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