JP2013094850A - Method of controlling arc welding and apparatus for arc welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that, in a welding employing a welding wire and a filler wire, which are consumable electrodes, a distance between a chip and a base material sometimes varies due to a shift in a set position of the base material, or a disturbance in a processing accuracy or the like of the base material, which causes a gap to be produced between a molten pool and the filler wire, and causes in turn a duration of the gap remaining in existence to be long because the filler wire is fed at a given rate, entailing a welding property to be impaired.SOLUTION: The method of controlling arc welding includes steps of: supplying a welding current to a preceding welding wire to generate an arc and form a molten pool on a base material; feeding a subsequently fed filler wire to contact the molten pool without supplying a welding current; in the case the filler wire is in contact with the molten pool, then feeding the filler wire at a first feeding rate; and in the case the filler wire and the molten pool are apart from each other, then feeding the filler wire at a second feeding rate higher than the first feeding rate.

Description

  The present invention relates to an arc welding control method and an arc welding apparatus that perform arc welding by feeding a filler wire close to a welding wire that is a consumable electrode.

  2. Description of the Related Art Conventionally, an arc welding control method for performing welding using a welding wire and a filler wire is known (see, for example, Patent Document 1).

  A conventional arc welding control method will be described with reference to FIGS. 3 and 4. FIG. 3 is a diagram showing a state of a welding portion for explaining a conventional arc welding control method. FIG. 4 is a diagram showing a filler wire feeding speed for explaining a conventional arc welding control method.

  In FIG. 3, the welding wire 8 is automatically fed in the direction of the base material 5 through the tip 10 provided in the torch 9. Then, electric power is supplied to the welding wire 8 through the tip 10, and the arc 4 is generated between the welding wire 8 and the base material 5. The arc 4 melts the welding wire 8 and the base material 5, thereby forming a molten pool 6 on the surface of the base material 5. In addition, the filler wire 17 that is not energized is automatically fed through the guide tip 18, and the tip end of the filler wire 17 is inserted into the molten pool 6. By doing in this way, the filler wire 17 is melted by the heat energy of the molten pool 6 in addition to the welding wire 8, and the amount of welding can be increased without increasing the heat input, which is the amount of heat given to the welded portion.

  Moreover, since the filler wire 17 which is not energized takes the thermal energy of the molten pool 6, the molten pool 6 is cooled and solidification of the molten pool 6 is promoted. As this effect, dripping of the molten metal that occurs during welding such as a standing posture and an upward posture is suppressed, the current range that can be welded is widened, and the efficiency of welding can be improved.

  Further, the amount of deposited metal can be increased without increasing the heat input, and the surface tension of the molten pool 6 can be reduced, so that the occurrence of humping and undercut can be suppressed, and the welding speed can be increased. It becomes possible.

  The filler wire 17 is fed at a first feeding speed V1, which is a predetermined feeding speed, as shown in FIG.

JP-A-6-63754

  The filler wire 17 feeding control in the conventional arc welding control method described above is fed at the first feeding speed V1 which is a predetermined feeding speed regardless of the melted state of the filler wire 17. However, at the production site, the distance between the chip 10 and the base material 5 may fluctuate due to disturbances such as a set position shift of the base material 5 and processing accuracy of the base material 5.

  When the distance between the tip 10 and the base material 5 becomes short, the welding current increases and the heat input to the base material 5 increases. In this case, since the melt amount of the filler wire 17 also increases, the melt amount of the filler wire 17 becomes larger than the feed amount of the filler wire 17 at the first feed speed V <b> 1 of the filler wire 17. A gap is generated.

  Further, when the distance between the chip 10 and the base material 5 suddenly increases, a gap is generated between the filler wire 17 and the base material 5.

  In any case, it takes time until the filler wire 17 is short-circuited to the molten pool 6 again, and during that time, the filler wire 17 is not short-circuited to the molten pool 6 and the above-described effect cannot be obtained.

  In order to solve the above-mentioned problems, an arc welding control method of the present invention is an arc welding control method for performing welding by feeding a welding wire that is a consumable electrode and a filler wire that is a consumable electrode, in the welding progress direction. On the other hand, the welding wire is preceded, the filler wire is followed, the welding wire is energized with a welding current to generate an arc to form a molten pool in the base material, and the following filler wire is formed. Is fed so as to contact the molten pool without passing a welding current, and when the filler wire is in contact with the molten pool, the filler wire is fed at a first feeding speed, When the molten pool is separated, the filler wire is fed at a second feeding speed that is faster than the first feeding speed.

  Further, the arc welding apparatus of the present invention includes a control unit for controlling welding output and feeding wire feeding, a power source unit for performing welding output based on the output of the control unit, and an output of the control unit. A welding wire feeding unit that controls the feeding speed of the welding wire based on the torch, and a torch that feeds the output of the power source unit to the welding wire fed by the welding wire feeding unit via a tip; A guide tip for inserting a filler wire into a molten pool formed in a base material when arc welding is performed using the torch, a filler wire control unit for controlling the feeding of the filler wire, and the filler wire control unit And detecting whether or not the filler wire feeding section for controlling the feeding speed of the filler wire is in contact with the filler pool formed on the base material and the filler wire. And a filler wire short-circuit detection power source that applies a voltage for filling between the filler wire and the base material, and the filler wire is in contact with the molten pool based on a detection result of a voltage between the filler wire and the molten pool. A filler wire short-circuit detection unit that detects whether or not the filler wire is in contact with the molten pool, and sends the filler wire at a first feeding speed. When the filler wire and the molten pool are separated from each other, the filler wire is fed at a second feeding speed that is faster than the first feeding speed.

  As described above, according to the present invention, when the filler wire and the molten pool are separated from each other, the second speed that is higher than the first feeding speed that is the feeding speed when the filler wire and the molten pool are in contact with each other. Since the filler wire is fed at a feeding speed of 1, the period during which the filler wire is separated from the molten pool can be shortened. As a result, even when a disturbance at the production site occurs, it is possible to suppress dripping of molten metal that occurs during welding, such as standing posture and upward posture, increase the amount of deposited metal, and decrease the surface tension of the molten pool Generation of humping and undercut can be stably suppressed, and weldability can be improved.

The figure which shows schematic structure of the arc welding apparatus in Embodiment 1 of this invention. (A) The figure which shows the time change of the voltage between the filler wire and base material in Embodiment 1 of this invention (b) The figure which shows the time change of the feeding rate of the filler wire in Embodiment 1 of this invention The figure which shows the state of the welding location for demonstrating the conventional arc welding control method The figure which shows the filler wire feed speed for demonstrating the conventional arc welding control method

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 and 2.

(Embodiment 1)
FIG. 1 is a diagram illustrating a schematic configuration of an arc welding apparatus according to the first embodiment. FIG. 2 is a diagram illustrating a change over time of the feeding speed of the filler wire and a change over time of the voltage between the filler wire and the base material when welding is performed by the arc welding apparatus according to the first embodiment.

  In FIG. 1, a welding power source device 1 includes a control unit 3 that performs control of welding output, control of the feeding speed of the welding wire 8, and the like, and a power source unit that adjusts and outputs the welding output using the output of the control unit 3 as input. 2 is provided. Further, the filler wire control device 11 includes a filler wire short-circuit detection power supply unit 12 that applies a detection voltage for detecting whether or not the filler wire 17 and the base material 5 are short-circuited, a filler wire short-circuit detection power supply unit 12, and a guide chip. The resistor 14 connected between the first and second electrodes 18 and the voltage between the molten pool 6 and the filler wire 17 formed in the base material 5 are detected to determine whether the filler wire 17 and the molten pool 6 are short-circuited. The filler wire short-circuit detecting unit 13 is provided, and the filler wire control unit 15 that controls the feeding speed of the filler wire 17 according to the short-circuit state between the filler wire 17 and the molten pool 6 detected by the filler wire short-circuit detecting unit 13 is provided.

  Moreover, the arc welding apparatus shown in FIG. 1 includes a welding wire feeding unit 7 that feeds the welding wire 8 with the output of the control unit 3 as an input, a tip 10 that feeds the output of the power source unit 2 to the welding wire 8, and A torch 9 that includes the tip 10 and guides the welding wire 8 to the welding location, a guide tip 18 that guides the filler wire 17 and is fixed to the torch 9 so as to follow the welding wire 8, and the filler wire control unit 15. The filler wire feeding unit 16 feeds the filler wire 17 based on the output. In addition, it arrange | positions so that the welding wire 8 may precede and the filler wire 17 may follow the welding progress direction. The torch 9 is used by being attached to a manipulator constituting an industrial robot, for example.

  Then, an arc 4 is generated between the welding wire 8 and the base material 5 by the electric power supplied from the power supply unit 2, and a molten pool 6 is formed in the base material 5.

  Since the filler wire short-circuit detection power supply unit 12 does not need to melt the filler wire 17, the current flowing through the filler wire 17 may be a very small value of 1 A or less, and no output for welding is required. can do. In addition, when the filler wire 17 and the molten pool 6 are short-circuited, the voltage between the filler wire 17 and the molten pool 6 decreases to near 0V, so the voltage applied by the filler wire short-circuit detection power supply unit 12 is 10V. If there is, it can be determined with certainty.

  Next, operation | movement of an arc welding apparatus is demonstrated using FIG. In FIG. 2, a period T <b> 1 indicates a period in which the molten pool 6 formed on the base material 5, the filler wire 17, and the base material 5 are short-circuited. In this case, the determination by the filler wire short-circuit detection unit 13 is easy, and it is determined that the short-circuit state exists. In the case of the short circuit state, the filler wire control unit 15 controls the feeding speed of the filler wire 17 to the first feeding speed V1 shown in FIG.

  In actual welding, the distance between the tip 10 and the base material 5 may fluctuate due to disturbances such as a set position shift of the base material 5 and processing accuracy of the base material 5.

  When the distance between the molten pool 6 formed in the base material 5 and the tip 10 is shortened by this disturbance, the welding current increases and the thermal energy supplied to the base material 5 increases. In this case, since the melt amount of the filler wire 17 also increases, the melt amount of the filler wire 17 becomes larger than the feed amount of the filler wire 17 at the first feed speed V1, and the molten pool 6 and the filler wire formed in the base material 5 are increased. A gap is generated between the two.

  Further, when the distance between the molten pool 6 formed in the base material 5 and the tip 10 suddenly increases due to the disturbance, the guide tip 18 is fixed to the torch 9, so that the filler wire 17 and the base material 5 A gap is generated between the two.

  In any of the above cases, the voltage detected by the filler wire short-circuit detection unit 13 is high during the period T2, which is a period in which a gap is generated between the filler wire 17 and the molten pool 6. During this period T2, since the voltage between the filler wire 17 and the molten pool 6 is high, the filler wire short-circuit detecting unit 13 determines that a gap is generated and outputs the same to the filler wire control unit 15. When the gap is generated, the filler wire control unit 15 changes the feeding speed of the filler wire 17 to the second feeding speed V2 higher than the first feeding speed V1, as shown in FIG. 2 (b). Control to increase.

  In this way, by increasing the feeding speed of the filler wire 17 to the second feeding speed V2, the filler wire 17 is short-circuited with the molten pool 6 at an early stage as compared with a case where the feeding speed is not increased. For example, the gap generation time of several hundred msec or more can be greatly shortened to several tens msec or less. Thereby, the effect obtained by short-circuiting the filler wire 17 to the molten pool 6, that is, suppression of dripping of the molten metal generated during welding such as a standing posture and an upward posture, an increase in the amount of deposited metal, and the molten pool Suppression of humping and undercut due to a decrease in surface tension can be stably obtained.

  When the feeding speed of the filler wire 17 is increased to the second feeding speed V2 and the filler wire 17 and the molten pool 6 are short-circuited, the filler wire control unit 15 causes the feeding of the filler wire 17 as shown in FIG. Control is performed so that the feeding speed is returned to the first feeding speed V1 lower than the second feeding speed V2.

  Note that the values of the first feeding speed V1 and the second feeding speed V2 are values obtained through experimental studies, for example, and may be adjusted for each production site. For example, the first feeding speed V1 may be about 1 m / min, and the higher the second feeding speed V2, the shorter the gap generation time may be. However, the first feeding speed V1 is likely to be pushed into the base material 5. Therefore, the second feed speed V2 is desirably 30 m / min or less at the maximum, and may be adjusted for each welding location.

  According to the present invention, when the filler wire and the molten pool are separated from each other, the filler wire is fed at the second feeding speed that is faster than the first feeding speed. Can be shortened to a short time. As a result, even when a disturbance at the production site occurs, it is possible to suppress dripping of molten metal that occurs during welding, such as standing posture and upward posture, increase the amount of deposited metal, and decrease the surface tension of the molten pool Since the occurrence of humping and undercut can be stably suppressed, the above-mentioned effect can be enhanced, and an arc welding control method and arc welding for performing welding while continuously feeding a welding wire and a filler wire as consumable electrodes. Industrially useful as a device.

T1 period (period in which filler wire and molten pool are short-circuited)
T2 period (period in which a gap is generated between the filler wire and the molten pool)
V1 1st feeding speed V2 2nd feeding speed 1 Welding power supply device 2 Power supply part 3 Control part 4 Arc 5 Base material 6 Molten pool 7 Welding wire feeding part 8 Welding wire 9 Torch 10 Tip 11 Filler wire control apparatus 12 Filler wire short-circuit detection power supply unit 13 Filler wire short-circuit detection unit 14 Resistor 15 Filler wire control unit 16 Filler wire feeding unit 17 Filler wire 18 Guide chip

Claims (2)

An arc welding control method for performing welding by feeding a welding wire as a consumable electrode and a filler wire as a consumable electrode,
With respect to the welding progress direction, the welding wire is preceded, the filler wire is followed, and a welding current is passed through the preceding welding wire to generate an arc to form a molten pool in the base material. The filler wire is fed so as not to pass a welding current to the molten pool,
When the filler wire is in contact with the molten pool, the filler wire is fed at a first feeding speed, and when the filler wire is separated from the molten pool, the first feeding is performed. An arc welding control method for feeding the filler wire at a second feeding speed faster than the speed. A control unit for controlling the welding output and feeding wire feeding;
A power supply unit for performing welding output based on the output of the control unit;
A welding wire feeding unit that controls the feeding speed of the welding wire based on the output of the control unit;
A torch for supplying the output of the power supply unit to the welding wire fed by the welding wire feeding unit via a tip;
A guide tip for inserting a filler wire into a molten pool formed in a base material when arc welding is performed using the torch;
A filler wire control unit for controlling the feeding of the filler wire;
A filler wire feeding unit that controls a feeding speed of the filler wire based on an output of the filler wire control unit;
A filler wire short-circuit detection power supply unit that applies a voltage between the filler wire and the base material to detect whether or not the molten pool formed on the base material is in contact with the filler wire;
A filler wire short-circuit detecting unit that detects whether or not the filler wire is in contact with the molten pool based on a detection result of a voltage between the filler wire and the molten pool and outputs the result to the filler wire control unit. ,
When the filler wire is in contact with the molten pool, the filler wire is fed at a first feeding speed. When the filler wire is separated from the molten pool, the filler wire is fed from the first feeding speed. An arc welding apparatus for feeding the filler wire at a fast second feeding speed.

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