JP2010194566A - Gma welding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a GMA welding method capable of carrying out high-efficiency welding while suppressing a spatter generation amount. <P>SOLUTION: In the GMA welding method, an arc Ac is generated by applying an arc voltage between a first contact chip 2 contacting with a wire W and a welding base material WP while feeding the wire W to the welding base material WP in shield gas SG. A first GMA welding current Iwa as a pulse current is made to flow between the first contact chip 2 and the welding base material WP, and a second GMA welding current Iwb as a constant current with its current value controlled to a constant value is made to flow between a second contact chip 3 contacting with the wire W and the welding base material WP. Accordingly, smooth droplet transfer of the wire W and the optimization of the length of the arc Ac are enabled and stable high-efficiency welding having a reduced amount of scattering spatter can be carried out. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a GMA welding method using a wire fed through a shielding gas as a consumable electrode.

  Conventionally, GMA welding has been proposed in which an arc is generated from the tip of a wire while feeding a wire as a consumable electrode in a shielding gas such as Ar. In this GMA welding method, it is important to balance the melting amount of the wire and the arc length to a desired size, for example, to realize stable welding with less spatter scattering.

  FIG. 2 shows an example of a welding apparatus used in a conventional GMA welding method (for example, Patent Document 1). The welding apparatus X shown in the figure includes a welding torch Y including a shield nozzle 91 and a plurality of contact tips 92, and a GMA welding power source PS. The plurality of contact chips 92 are each provided with a through hole, and are arranged so that they are aligned. A wire W fed at a feeding speed Fw is inserted through these through holes. The plurality of contact tips 92 are connected to the GMA welding power source PS. An arc current Iw for generating an arc Ac is supplied from the GMA welding power source PS. A shield gas SG such as Ar is supplied between the shield nozzle 91 and the plurality of contact chips 92.

  In this welding method, arc current Iw is supplied from wire W to welding base material WP using any one of a plurality of contact tips 92. Thereby, it is possible to adjust the magnitude of the Joule heat generated in the wire W, and it is intended to adjust the melting amount of the wire W and the length of the arc Ac to a desired magnitude. Such a configuration is a plasma GMA welding method using a consumable electrode arc generated from a consumable electrode and a non-consumable electrode arc generated from a non-consumable electrode so as to wrap around the consumable electrode arc as described in Patent Document 2. It can also be applied to.

  However, in the so-called high-efficiency welding in which the welding speed and the feeding speed Fw of the wire W are relatively fast, the melting amount of the wire W is further increased. As the melting amount of the wire W increases, it becomes more difficult to adjust the length of the arc Ac to a desired size. As a result, there has been a problem that welding becomes unstable, such as an increased amount of spatter.

JP-A-52-7846 JP 2008-229641 A

  The present invention has been conceived under the circumstances described above, and an object thereof is to provide a GMA welding method capable of performing high-efficiency welding while suppressing the amount of spatter generated.

  The GMA welding method provided by the present invention applies an arc voltage between a contact electrode brought into contact with the wire and the welding target material while feeding the wire in a shielding gas toward the welding target material. A GMA welding method for generating an arc by causing a pulse current to flow between the contact electrode and the material to be welded and between the additional contact electrode brought into contact with the wire and the material to be welded. In addition, a constant current whose current value is controlled to a constant value is supplied.

  According to such a configuration, it is possible to smoothly transfer the droplet of the wire and optimize the length of the arc, and perform stable high-efficiency welding with a small amount of spatter scattering.

  In a preferred embodiment of the present invention, the additional contact electrode is in contact with the wire at a position closer to the material to be welded than the contact electrode. Such a configuration is suitable for avoiding the generation of excessive Joule heat in the wire.

  Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

It is a system configuration figure showing an example of the GMA welding method concerning the present invention. It is a system block diagram which shows an example of the conventional GMA welding method.

  Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

  FIG. 1 shows an example of a welding apparatus used in the GMA welding method according to the present invention. The welding apparatus A of this embodiment includes a welding torch B, a first GMA welding power source PSA, a second GMA welding power source PSB, a feeding roller Rw, and a feeding motor WM.

  The welding torch B has a structure in which a first contact tip 2 and a second contact tip 3 are arranged on a concentric shaft in the shield gas nozzle 1. The welding torch B is moved relative to the welding base material WP while being held by a normal robot (not shown).

  The first contact chip 2 is made of, for example, Cu or Cu alloy, and is provided with a through hole 21. A wire W as a consumable electrode is fed to the through hole 21. The second contact chip 3 has a substantially cylindrical shape, and is made of, for example, Cu or a Cu alloy having a water cooling mechanism (not shown). A through hole 31 is provided in the second contact chip 3. The through hole 21 and the through hole 31 are sized so that the inner surfaces thereof rub against the wire W. The through hole 31 is located closer to the tip of the wire W in the feeding direction than the through hole 21. The wire W is fed by a feed roller Rw using a feed motor WM as a drive source.

  The shield gas nozzle 1 has a substantially cylindrical shape, and is made of, for example, Cu or a Cu alloy having a water cooling mechanism (not shown). The shield gas nozzle 1 is provided with an opening 11. A shield gas SG such as Ar is supplied between the shield gas nozzle 1 and the second contact chip 3. The shield gas SG is ejected from the opening 11. The wire W is fed through the jetting shield gas SG.

  The first GMA welding power source PSA applies the first GMA welding voltage Vwa between the wire W and the welding base material WP via the first contact tip 2 to flow the first GMA welding current Iwa as a pulse current. Is the power source. Further, a feed control signal FC is sent from the first GMA welding power source PSA to the feed motor WM. When the first GMA welding voltage Vwa is applied from the first GMA welding power source PSA, the wire W is set to the + side.

  The second GMA welding power source PSB applies a second GMA welding voltage Iwb as a constant current by applying a second GMA welding voltage Vwb between the wire W and the welding base material WP via the second contact tip 3. Is the power source. When the second GMA welding voltage Vwb is applied from the second GMA welding power source PSB, the wire W is set to the + side.

  In this embodiment, high-efficiency welding with a feeding speed Fw of about 10 m / min is performed. In this case, the first GMA welding voltage Vwa is about 30 V, the frequency of the first GMA welding current Iwa that is a pulse current is 200 Hz, the base current value is 50 to 60 A, the peak current value is 450 to 460 A, and the average current value is about 180 A. . On the other hand, the second GMA welding voltage Vwb is about 30V, and the second GMA welding current Iwb having a constant current value is about 100A.

  Next, the effect | action of the GMA welding method of this embodiment is demonstrated.

  The average current value obtained by summing the first GMA welding current Iwa and the second GMA welding current Iwb is about 280A. If only the pulse current is supplied at an average current value of about 280 A, in order to realize appropriate droplet transfer of the wire W, it is common to set the frequency to about 280 to 300 Hz. When welding is performed under these conditions, high-efficiency welding with a feeding speed Fw of about 10 m / min is possible, but the amount of spatter scattering becomes excessive, about 1-2 g / min.

  On the other hand, according to the tests by the inventors, in the present embodiment, the amount of spatter scattered was suppressed to a very small amount of about 0.5 g / min. This is considered to be due to the fact that the frequency of the first GMA welding current Iwa is relatively low at about 200 Hz, even though the total of the average current values is about 280A. In such stable welding, not only the first GMA welding current Iwa as a pulse current but also the second GMA welding current Iwb as a constant current are flowed in an overlapping manner, thereby realizing appropriate droplet transfer of the wire W, It can be realized only by increasing the amount of energy supplied to the wire W.

  Also, bringing the second contact tip 3 into contact with the wire W closer to the tip of the wire W than the first contact tip 2 avoids excessive Joule heat from being generated in the wire W by the second GMA welding current Iwb. Suitable for

  The GMA welding method according to the present invention is not limited to the above-described embodiment. The specific configuration of the GMA welding method according to the present invention can be modified in various ways.

  The GMA welding method according to the present invention is not limited to the one that generates only the above-described consumable electrode arc, and is applied to, for example, a so-called plasma GMA welding method that generates a consumable electrode arc and a non-consumable electrode arc surrounding the consumable electrode arc. May be.

A welding apparatus Ac arc B welding torch FC feeding control signal Fw feeding speed Iwa first GMA welding current Iwb second GMA welding current PSA first GMA welding power source PSB second GMA welding power source Rw feeding roller W wire WM feeding motor WP welding mother Material (material to be welded)
1 Shield nozzle 2 First contact tip (contact electrode)
3 Second contact tip (additional contact electrode)

Claims (2)

While feeding the wire through the shielding gas toward the material to be welded,
A GMA welding method for generating an arc by applying an arc voltage between a contact electrode brought into contact with the wire and the material to be welded,
While passing a pulse current between the contact electrode and the material to be welded,
A GMA welding method, wherein a constant current whose current value is controlled to a constant value is allowed to flow between the additional contact electrode brought into contact with the wire and the material to be welded.   The GMA welding method according to claim 1, wherein the additional contact electrode is in contact with the wire at a position closer to the welding target material than the contact electrode.

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