JP2016036833A - Two-electrode simultaneous welding device, and two-electrode simultaneous welding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a two-electrode simultaneous welding device and a two-electrode simultaneous welding method capable of solving the problems in which the GMA welding of the recent years is varied in the period of an electric current waveform at each time when a welding power source detects the welding state, so that the GMA and the non-consumable welding phase are deviated, if the GMA welding and non-consumable welding are mutually performed at a constant interval, to cause an interference of arcs in any way thereby to make it difficult to weld stably.SOLUTION: An electric current waveform of GMA welding is directly detected to determine a low current region having no interference of an arc so that the simultaneous welding is performed while making controls, in which an arbitrary timing, an arbitrary period and non-consumable welding can be performed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a two-electrode simultaneous welding method and two-electrode simultaneous apparatus by arc welding of metal.

  A welding apparatus capable of performing GMA (Gas Metal Arc) welding and non-consumable welding, for example, TIG (Tungsten Inert Gas) welding at the same time, is advantageous in improving the welding speed and increasing the penetration depth. It is. In addition, the advantages of both the TIG welding method in which a high-quality weld is obtained because of a non-consumable electrode and the GMA welding method capable of overlaying can be utilized. However, since GMA welding and TIG welding are generally welding methods in which arc discharge is performed, an attractive force and a repulsive force are generated between the arcs due to a magnetic field generated when arcs are simultaneously welded. Since the attractive force and repulsive force increase in proportion to the welding current, large attractive force and repulsive force are generated in welding with a large current or pulse welding with a large peak current, and stable welding is difficult. Therefore, conventionally, as shown in FIG. 3 of Patent Document 1, arc welding is performed by shifting the phase so that the peak of the current waveform of GMA welding and the peak of the waveform of TIG welding are interchanged. Was suppressed.

JP2008-207213 (FIG. 3)

  For simultaneous welding of GMA welding and non-consumable welding, for example, TIG welding, it is necessary to avoid arc interference, so both phases must be set to pulse mode and the phases must be shifted so that the peaks do not overlap each other. There is. However, since GMA welding is a consumable electrode that melts the electrode, the molten state of the electrode being welded changes every moment. Therefore, in order to perform stable welding in recent GMA welding power sources, the welding power source has a feedback control mechanism that detects voltage or current and changes the current cycle from time to time. For this reason, when GMA welding and TIG welding are performed simultaneously, even if the welding is started with the phase shifted so as to avoid the overlap between the peak current time of GMA welding and the peak current time of TIG welding, Since the frequency of GMA welding is changed by the action of the feedback control mechanism, the peak timings of the current welding power sources overlap each other, and arc interaction occurs, making stable welding difficult.

  In the two-electrode simultaneous welding apparatus of the present invention, a GMA electrode to which current is supplied from a GMA welding power source, a current detection unit for measuring a current value of the current, a control unit for outputting a command signal corresponding to the current value, an arc And a non-consumable welding apparatus having a non-consumable electrode for generating a current, and a current flowing through the non-consumable electrode is controlled by a command signal.

  In the two-electrode simultaneous welding apparatus of the present invention, a GMA electrode to which current is supplied from a GMA welding power source, a current detection unit for measuring a current value of the current, a control unit for outputting a command signal corresponding to the current value, an arc And a non-consumable welding apparatus having a non-consumable electrode that generates electric current, and the current flowing through the non-consumable electrode is controlled by a command signal. Simultaneous welding that reliably avoids this can be performed.

It is a block diagram of the two-electrode simultaneous welding apparatus in Embodiment 1 of this invention. It is a current wave form diagram of pulse GMA welding in Embodiment 1 of the present invention. It is a block diagram of the 2 electrode simultaneous welding apparatus in Embodiment 2 of this invention. It is a figure for showing the comparative example in Embodiment 2 of the present invention. It is a block diagram of the 2 electrode simultaneous welding apparatus in Embodiment 3 of this invention. It is a block diagram of the 2 electrode simultaneous welding apparatus in Embodiment 3 of this invention.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram of a two-electrode simultaneous welding apparatus according to Embodiment 1 of the present invention. More specifically, FIG. 1 shows a simultaneous welding method in which a TIG electrode 1 is preceded and a GMA electrode 2 is followed. A TIG welding power source 5 is connected to 1 and a GMA welding power source 4 is connected to the GMA electrode 2. A direct current detection line 6 for directly reading a current value is connected between the GMA power source 4 and the GMA electrode 2 through which the welding current flows. This is a configuration provided. In the drawings, the same reference numerals denote the same or corresponding parts, and this is common to the entire text of the specification and all the drawings. Furthermore, the form of the constituent elements appearing in the whole specification is merely an example, and is not limited to these descriptions.

  Here, the distance between the electrodes is set to 10 mm or less so that heat input by arc discharge generated from the two electrodes (TIG electrode 1 and GMA electrode 2) is given to one molten pool. Both welding methods are pulse welding methods. GMA welding preferably has a peak current of 300A to 500A, a base current of 60A or less, and a repetition frequency of 200Hz or less, and TIG welding preferably has a peak current of 150A or more and a base current of 60A or less. The welding speed is preferably 100 mm / min to 2000 mm / min. The specific operation is as follows.

  FIG. 2 is a current waveform diagram of pulse GMA welding in the first embodiment of the present invention. The current detection line 6 is directly connected to the circuit of the GMA power source to directly detect the welding current of GMA welding. For example, in pulse GMA welding, the current waveform is as shown in FIG. 2, and there is a rectangular section with a high current value. The direct current detection line 6 is connected to a control device 7, and the control device 7 has a function of reading a current value and sending a command to the TIG power source according to the value.

  When the arc current is small, since the mutual interference of arcs is small at 60 A or less and the welding is not difficult, for example, 60 A is set in the control device 7 as a threshold value. If the current value obtained by the direct current detection line 6 is equal to or greater than the threshold value, a peak OFF command is sent to the TIG power source to stop the peak arc generation, and a base arc state at a low current, for example, 60 A is set. If it is below the threshold value, a peak ON command is sent to the TIG power source to generate a TIG arc peak, and a high current arc, for example, 150 A, which provides the desired penetration, is generated.

  With this configuration, GMA welding can be performed stably as in the case of single welding, and TIG welding peaks only in the section where the welding current of GMA welding is low, so simultaneous welding that reliably avoids arc interference is possible. is there.

  Since GMA welding is a consumable electrode, the electrode itself melts and is deposited on the base material as a build-up. For this reason, since there is build-up between the arc and the base material, arc heat is not directly transmitted to the base material, heat input is hindered, and insufficient melting may occur. In particular, this tendency is remarkable at the start of welding and in metals such as aluminum and copper having high thermal conductivity. However, since TIG welding is a non-consumable electrode, there is nothing to block the arc heat to the base material as described above, and the base material can be reliably melted if the welding peak current is 150 A or more. For this reason, a preform | base_material can be reliably fuse | melted by performing the simultaneous welding which the TIG welding method preceded. By directly detecting the welding current of GMA welding and reliably shifting the timing of arc generation every time, stable simultaneous welding is possible.

  In addition, the limit of about 1000 mm / min is the limit for a single GMA weld, and if the speed is further increased, the thickness of the weld bead becomes a humping bead that periodically changes. This is mainly due to insufficient heat input due to the increase in speed and the base material is not heated sufficiently. However, if the TIG power supply is preceded, the base material can be melted in advance, so there is insufficient heat input. As a result, the welding speed can be increased up to twice as much as possible, and high-speed and high-quality welding can be performed utilizing the advantages of the TIG welding method.

  Furthermore, in order to stabilize the welding state in the simultaneous welding, it is not always appropriate to simply perform welding alternately at regular intervals. Rather than performing GMA welding and TIG welding alternately on a one-to-one basis, for example, a two-to-one cycle balance may be more appropriate, such as two cycles of GMA welding and one cycle of TIG welding.

  For example, the number of TIG peaks (number of pulses) generated in the low current section of GMA welding can be adjusted by programming in advance the command of the control mechanism 7 in the case of the threshold value or less. When the pulse interval is changed in the TIG welding method, the weld pool is vibrated by the pressure of the TIG arc, and the weld structure can be refined by the frequency, but the pulse number is also reduced in the two-electrode simultaneous welding method. By increasing, vibration can be given to the molten pool. Under these conditions, the weld pool of TIG welding method and GMA welding method is a series, so the vibration of the weld pool by TIG arc also works effectively on the weld pool of GMA welding, and the weld structure can be refined. it can.

  A GMA electrode to which current is supplied from the GMA welding power source, a current detection unit that measures the current value of the current, a control unit that outputs a command signal according to the current value, and a non-consumable electrode that generates an arc According to the two-electrode simultaneous welding device, which has a non-consumable welding device and the current flowing through the non-consumable electrode is controlled by a command signal, the command signal interferes with the arc of GMA welding and the arc of non-consumable welding. Therefore, simultaneous welding can be performed while reliably avoiding arc interference even if the waveform period varies. This is because non-consumable welding is performed when the value of the current flowing through the GMA electrode is equal to or less than a predetermined value.

  As described above, the current waveform of GMA welding is directly detected, and a low current region in which no arc interference occurs is determined. In the meantime, control can be performed so that TIG welding can be performed at an arbitrary timing and at an arbitrary time. Simultaneous welding can be performed with appropriate control according to the welding environment and conditions.

Embodiment 2. FIG.
FIG. 3 is a configuration diagram of the two-electrode simultaneous welding apparatus according to the second embodiment of the present invention. More specifically, FIG. 3 shows an example in which vertical welding is performed with the same configuration as that of the first embodiment. Normally, in the vertical welding, the molten pool hangs down due to gravity, and in the vertical welding, the molten pool is pulled down due to gravity (see FIG. 4). In particular, in vertical downward welding, the molten pool hangs down in the welding direction, and the molten material intervenes between the electrode and the workpiece, preventing the heat input to the workpiece due to arc discharge and preventing stable penetration. It becomes a quality problem. On the other hand, in longitudinally upward welding, continuous welding is not performed in order to prevent dripping, and welding is performed while cutting the arc to quickly solidify the molten pool. However, since heat input is reduced, insufficient penetration occurs. Here, the vertical welding, which is the most severe condition, has been described, but the same problem occurs even at an inclination of 45 degrees or more.

  In the present embodiment, TIG welding is responsible for the penetration of the base material, and GMA welding is responsible for the build-up. It is known that GMA welding can preferentially melt wires by setting the current waveform to reverse polarity. In this configuration, TIG welding precedes and the base material is melted, so heat input by GMA welding is only necessary for melting the wire.

  Conventionally, since GMA welding alone simultaneously melts the base material and builds up with a wire, it has been necessary to exceed the melting point of the metal over a wide range. When the peak temperature is one point, the temperature distribution has a distribution in which the temperature decreases radially from the peak temperature due to its diffusivity. For this reason, the peak temperature needs to be higher than the melting point in order to set the wide range to a high temperature, here the melting point. The larger the range above the melting point, the higher the peak temperature must be.

  However, by dividing the heat source into two as in this configuration, the temperature distribution in which the peak temperature is two points has a temperature distribution in which the equivalent range is the melting point at a lower peak temperature than when the peak temperature is one. can get. By such a principle, the maximum temperature of the molten pool can be suppressed by simultaneous welding having two heat sources. Since the viscosity of metal generally decreases as the temperature increases, by using this configuration, the drooping of the molten pool can be solved by suppressing the maximum temperature, and good vertical welding becomes possible. Furthermore, since heat is reliably input to the base metal during the preceding TIG welding, stable penetration can be obtained, and the lack of penetration can be resolved even with welding at 45 degrees or more or in the vertical direction.

  A GMA electrode to which current is supplied from the GMA welding power source, a current detection unit that measures the current value of the current, a control unit that outputs a command signal according to the current value, and a non-consumable electrode that generates an arc According to the two-electrode simultaneous welding device, which has a non-consumable welding device and the current flowing through the non-consumable electrode is controlled by a command signal, the command signal interferes with the arc of GMA welding and the arc of non-consumable welding. Therefore, simultaneous welding can be performed while reliably avoiding arc interference even if the waveform period varies. This is because non-consumable welding is performed when the value of the current flowing through the GMA electrode is equal to or less than a predetermined value.

Embodiment 3 FIG.
6 and 7 are configuration diagrams of a two-electrode simultaneous welding apparatus according to Embodiment 3 of the present invention. The first and second embodiments differ from the first and second embodiments in the configuration in which a heat source by a TIG welding power source is a plasma heat source. The current flowing through the plasma electrode 10 is controlled by a command signal from the control device 7. FIG. 6 and FIG. 7 show the plasma-GMA simultaneous welding method preceded by the plasma electrode 10, FIG. 6 shows a horizontal welding example, and FIG. 7 shows a vertical welding example. Then, GMA welding will continue.

  The distance between the electrodes is set to 10 mm or less so that heat input by arc discharge generated from the two electrodes is given to one molten pool. In the GMA welding, it is desirable that the peak current is 300 A to 500 A, the base current is 60 A or less, and the repetition frequency is 200 Hz or less by the pulse welding method as in the conventional configuration. The plasma welding method preferably has a peak current of 100 A or more and a base current of 60 A or less. By using plasma welding, the welding speed can be improved more than when TIG welding is used, and the welding speed is preferably 100 mm / min to 3000 mm / min. Furthermore, by using plasma welding, it is possible to reduce the heat input of about 30% as a leading heat source than during TIG welding, and the maximum temperature of the molten pool can be suppressed, so that dripping of the molten pool can be further suppressed. it can.

  As described above, a GMA electrode to which current is supplied from the GMA welding power source, a current detection unit that measures the current value of the current, a control unit that outputs a command signal corresponding to the current value, and a plasma electrode that generates an arc A two-electrode simultaneous welding method using a plasma welding apparatus equipped with a non-consumable welding when non-consumable welding precedes GMA welding and the current value flowing through the GMA electrode is below a predetermined value 2 This is an electrode simultaneous welding method, and even when welding is performed at an inclination of 45 degrees or more or in a vertical direction, simultaneous welding can be performed while reliably avoiding arc interference.

  1 TIG electrode, 2 GMA electrode, 3 base material, 4 GMA welding power source, 5 TIG welding power source, 6 direct current detection line, 7 control device, 8 welding current waveform of GMA welding, 9 bead dripping due to gravity, 10 plasma Electrode, 11 Plasma welding power source.

Claims (10)

GMA electrode supplied with current from GMA welding power source,
A current detector for measuring the current value of the current;
A control unit that outputs a command signal according to the current value;
A non-consumable welding device with a non-consumable electrode for generating an arc,
The two-electrode simultaneous welding apparatus, wherein a current flowing through the non-consumable electrode is controlled by the command signal. 2. The two-electrode simultaneous welding apparatus according to claim 1, wherein the command signal is a signal for controlling the arc of GMA welding and the arc of non-consumable welding so as not to interfere with each other. GMA electrode supplied with current from GMA welding power source,
A current detector for measuring the current value of the current;
A control unit that outputs a command signal according to the current value;
A plasma welding apparatus having a plasma electrode for generating an arc;
The two-electrode simultaneous welding apparatus, wherein a current flowing through the plasma electrode is controlled by the command signal. 4. The two-electrode simultaneous welding apparatus according to claim 3, wherein the command signal is a signal for controlling the GMA welding arc and the plasma welding arc so as not to interfere with each other. GMA electrode supplied with current from GMA welding power source,
A current detector for measuring the current value of the current;
A control unit that outputs a command signal according to the current value;
A two-electrode simultaneous welding method using a non-consumable welding apparatus having a non-consumable electrode for generating an arc,
A two-electrode simultaneous welding method in which non-consumable welding precedes GMA welding, and a current flowing through the non-consumable electrode is controlled by the command signal. 6. The two-electrode simultaneous welding method according to claim 5, wherein the command signal performs non-consumable welding when a current value flowing through the GMA electrode is equal to or less than a predetermined value. The two-electrode simultaneous welding method according to claim 5 or 6, wherein welding is performed at an inclination of 45 degrees or more or in a vertical direction. GMA electrode supplied with current from GMA welding power source,
A current detector for measuring the current value of the current;
A control unit that outputs a command signal according to the current value;
A two-electrode simultaneous welding method using a plasma welding apparatus having a plasma electrode for generating an arc,
A two-electrode simultaneous welding method in which non-consumable welding precedes GMA welding, and a current flowing through the non-consumable electrode is controlled by the command signal. 9. The two-electrode simultaneous welding method according to claim 8, wherein the command signal performs plasma welding when the value of a current flowing through the GMA electrode is equal to or less than a predetermined value. The two-electrode simultaneous welding method according to claim 8 or 9, wherein welding is performed at an inclination of 45 degrees or more or in a vertical direction.

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