JP3615097B2 - Combined welding method of laser and arc - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to composite welding of laser welding and arc welding.
[0002]
[Prior art]
TLG, when performing arc welding by using a welding or the like MLG, C0 2, _MAG, as shown in FIG. 3, by moving the welding torch 1 with respect to the material to be welded 2, to move the weld pool On the other hand, the material to be welded 2 and the filler material fed from the torch 1 are melted by the plasma 5 by arc discharge and fused with the material 2 to be welded.
In FIG. 3, 6 is a welding beat and 8 is a discharge electrode.
[0003]
In contrast to the arc welding described above, laser welding is capable of condensing a laser beam onto a material to be welded by an optical system and obtaining deep penetration with a high energy density.
[0004]
In recent years, a welding method in which laser light and arc welding are combined has been attempted. For example, there are techniques disclosed in Japanese Patent Laid-Open Nos. 7-246484 and 10-216972.
[0005]
The technique described in Japanese Patent Application Laid-Open No. 7-246484 is intended to stabilize the arc by plasma generated by laser light and obtain a good weld.
That is, the laser beam is irradiated to a position deviated from the irradiation position of the plasma torch behind the moving direction of the plasma torch. Thereby, even if the welding moving speed is set to a high speed, the plasma generated based on the laser beam irradiation supplements the discontinuity of the plasma arc, thereby obtaining a stable arc discharge.
[0006]
In addition, the technique described in Japanese Patent Laid-Open No. 10-216972 irradiates a material to be welded with a laser beam prior to an arc welding position, and provides a root gap and a laser spot and an arc welding position. Thick plates are welded by keeping the distance between them appropriate.
[0007]
[Problems to be solved by the invention]
Incidentally, the above-described, T1G, in the case of arc welding, such as _M1G, C0 2, MAG, it is difficult to obtain deep penetration at high speed.
For this reason, in the technique described in Japanese Patent Laid-Open No. 7-246484, the penetration depth 15 is shallow, a butt welding of a thin plate having a plate pressure of about several millimeters is possible, and the thick plate is difficult to weld.
[0008]
In the technique described in Japanese Patent Application Laid-Open No. 10-21697, a welding method has been proposed in which deep welding is obtained at high speed by combining arc welding and laser welding.
[0009]
However, in the welding method described in Japanese Patent Application Laid-Open No. 10-21697, plasma 5 due to arc discharge is almost always generated from the consumable electrode 8 as shown in FIG. For this reason, the power of the laser beam 12, which is the main factor of the deep penetration action, is absorbed and scattered by the plasma 5 by arc discharge and acts in a direction that inhibits the effect of the laser beam 12.
[0010]
Therefore, there is a problem that the effective effect of the laser beam 12 cannot be imparted to the workpiece (workpiece), and it has been difficult to obtain a penetration depth 15 greater than this.
[0011]
An object of the present invention, TLG, MLG, C0 2, in the hybrid welding method of the laser and the arc of the arc welding and laser welding and composite _MAG welding, yet simple, plasma laser beam is generated by an arc discharge It is to realize a composite welding method that can effectively exhibit the effect of laser welding without being hindered by the above, and can obtain the penetration of the material to be welded.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is configured as follows.
(1) In a combined laser and arc welding method for welding a material to be welded by combining laser light by laser welding and arc heat by arc welding, the laser beam is irradiated to the material to be welded from a laser oscillator; A welding power is supplied between the welding material and the welding torch from the welding power source so that the arc discharge repeats disappearance and generation between the welding material and the plasma generated by the arc discharge disappears.
[0013]
(2) Preferably, in (1), the welding power is in the form of a pulse having a pulse interval such that plasma generated by arc discharge is eliminated .
[0014]
(3) In addition, preferably, in (1), the welding power is an alternating current having an interval enough to eliminate the melting of the plasma generated by arc discharge .
[0015]
(4) In a combined laser and arc welding apparatus for welding a material to be welded by combining laser light by laser welding and arc heat by arc welding, a laser oscillator for irradiating the material to be welded with laser light; A laser power source of a laser oscillator, a welding power source for supplying a welding power to cause arc discharge between the welding material and the torch from a welding power source, and disappearance and generation of the arc discharge between the welding material and And a controller for controlling the welding power source so as to eliminate the plasma generated by the arc discharge.
[0016]
When the welding conditions are set as described above, the plasma due to arc discharge is repeatedly lost and generated. For this reason, the focused laser beam can give the maximum power to the material to be welded during the plasma disappearance time due to arc discharge.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
First, the principle of the present invention will be described.
As described above, in the laser and arc combined welding method, plasma due to arc discharge is almost always generated, and the plasma due to arc discharge absorbs and scatters the power of laser light.
[0018]
Therefore, if the plasma caused by the arc discharge disappears periodically or almost periodically, a period in which the power of the laser beam is not hindered by the plasma caused by the arc discharge can be secured. Deep penetration of the material can be obtained.
[0019]
That is, in the first embodiment of the present invention, when welding is performed by combining laser welding and arc welding, the welding voltage (current) of arc welding is changed to a pulse or alternating current.
[0020]
Preferably, when the welding voltage (current) of arc welding is set to a pulse shape, the pulse interval (although depending on the welding conditions) at which arc discharge disappears is about 0. This is realized by setting the base voltage of the pulse voltage so as not to cause arc discharge at intervals of 1 ms or more.
[0021]
In addition, when the welding voltage (current) of arc welding is AC, for example, it may be about 100 Hz, although it varies depending on the welding conditions.
[0022]
When the above conditions are set, the arc discharge repeats disappearance and generation, and no plasma is generated by arc discharge during the arc discharge disappearance time. Can give the maximum power to the workpiece.
[0023]
Next, an example of an apparatus for performing the above-described combined welding of a laser and an arc will be described.
FIG. 1 is a schematic configuration diagram of an example of a welding apparatus that performs the above-described combined welding of a laser and an arc. In FIG. 1, a laser beam 12 output from a laser oscillator 13 passes through a transmission path, is reflected by a condensing mirror 11, and is condensed on a workpiece 2 via a laser nozzle 16.
[0024]
The workpiece 2 is fixed horizontally by a welding jig 18. A shielding gas (for example, helium gas) is injected from the laser processing nozzle 16 toward the workpiece 2 coaxially with the laser beam 12 to shield the workpiece 2 (workpiece). .
[0025]
Further, the arc welding filler of the welding torch 1 protruding from the electrode 8 is disposed near the laser spot, while being supported in a backward inclined position by 40 degrees in the welding progress direction near the laser spot on the surface of the workpiece 2. The welding torch 1 also injects a shielding gas (for example, argon, which may be different from the shielding gas injected from the laser emission nozzle 16).
[0026]
Reference numeral 19 denotes a filler feeding device from which the arc welding filler of the welding torch 1 is fed. The workpiece 2 is fixed on a table (XY table) 17 by a fixing jig 18, and the table 17 is moved by a motor 7.
[0027]
Reference numeral 20 denotes a welding power source. A welding voltage or a welding current is supplied from the welding power source 20 between the welding electrode 8 of the welding torch 1 and the material to be welded 2. Reference numeral 14 denotes a laser power source for the laser oscillator 13. Reference numeral 21 denotes a controller. The controller 21 controls operations of the laser oscillator 13, the laser power source 14, the welding power source 20, and the motor 20.
[0028]
In the welding apparatus shown in FIG. 1, the welding voltage or welding current supplied from the welding power source 20 between the welding electrode 8 and the material to be welded 2 is pulsed or alternating current. When the conditions are set as described above, the plasma 9 is generated by the laser beam but the plasma 5 is not generated by the arc discharge as shown in FIG. 2 during the arc discharge disappearance time. The condensed laser beam 12 can give the maximum power to the workpiece 2. Thereby, the penetration depth 15 is deeper than that in the case where the plasma 5 by arc discharge is not lost (see FIG. 4).
[0029]
As described above, according to the first embodiment of the present invention, when welding is performed by combining laser welding and arc welding, the welding voltage (current) of arc welding is set to pulsed or alternating current. The arc discharge repeats disappearance and generation, and during the arc discharge disappearance time, the generation of plasma due to the arc discharge can be prevented, and the maximum power can be given to the laser beam to the workpiece.
[0030]
Therefore, it is a simple combination of laser and arc that allows laser beam to be effectively shielded by plasma generated by arc discharge and to effectively demonstrate the effects of laser welding and to achieve the penetration of the welded material. A welding method can be realized.
[0031]
Next, a second embodiment of the present invention will be described.
In the first embodiment described above, the welding voltage (current) for arc welding is pulsed or alternating, but in the second embodiment of the present invention, the welding voltage (current) for arc welding is direct current.
[0032]
By the way, in arc welding, an electrode wire is melted by arc heat to form droplets and moves to a molten pool of a material to be welded. In this case, a short-circuit transition phenomenon in which the discharge electrode and the material to be welded are short-circuited may occur depending on conditions such as the size and shape of the droplet to be transferred and the transfer speed.
[0033]
At the occurrence of this short-circuit transition phenomenon, the discharge electrode and the material to be welded are energized without plasma, and the generated plasma is cooled and disappears for a moment. After energization, it is melted by the Joule heat of the flowing current, and is generated again by the metal vapor and the thermoelectrons.
[0034]
In the second embodiment of the present invention, the short-circuit transition phenomenon described above is actively used, and the disappearance and generation of the plasma due to the arc discharge are repeated so that the power of the laser beam when the plasma disappears due to the arc discharge. Is used effectively to obtain a deep penetration of the material to be welded.
[0035]
Next, an example of conditions for causing the above-described short-circuit transition phenomenon is shown below.
As for the shielding gas, helium is set to 201 / min in the laser nozzle 16 and helium is set to 201 / min in the welding chamber 1 as in the laser nozzle 16. The welding current is 250 A, and the welding voltage is 25 V. The welding speed is 1 m / min and the laser is 5 kW.
[0036]
When welding is performed under the above-described conditions, the supplied welding voltage (current) is energized without passing through the plasma 5 when short-circuited, and the plasma 5 cools and disappears for a moment. The disappeared plasma 5 is melted by Joule heat of the flowing current after the filler wire is energized to the workpiece 2 and is generated again by the metal vapor and the thermoelectrons. Within the short circuit transition time, the plasma 5 is in a cold state, and the laser beam 12 is not inhibited by the plasma 5, and the welded material 2 is melted by the power of the irradiated laser beam 12 and deep penetration is obtained.
[0037]
As a result, in the conventional method, the laser beam is scattered and absorbed by the plasma 5, and the phenomenon in which the energy of the laser beam 12 is not effectively transmitted in the depth direction has occurred. In the second embodiment, the phenomenon that the energy is not effectively transmitted is avoided, and the maximum laser penetration is obtained as shown in FIG.
[0038]
That is, according to the second embodiment of the present invention, when laser welding and arc welding are combined and welding is performed, the welding condition for arc welding is set as a condition for causing a short-circuit transition phenomenon, thereby causing a short-circuit transition. Sometimes, plasma caused by arc discharge can be extinguished to give maximum power to the laser beam for the material to be welded.
[0039]
Therefore, it is a simple combination of laser and arc that allows laser beam to be effectively shielded by plasma generated by arc discharge and to effectively demonstrate the effects of laser welding and to achieve the penetration of the welded material. A welding method can be realized.
[0040]
【The invention's effect】
According to the present invention, when welding is performed by combining laser welding and arc welding, the welding voltage (current) of arc welding is changed to a pulse or alternating current, so that the arc discharge repeatedly disappears and is generated. By reducing the generation of plasma due to arc discharge during the discharge disappearance time, it is possible to give the maximum power to the laser light for the workpiece.
[0041]
Therefore, it is a simple combination of laser and arc that allows laser beam to be effectively shielded by plasma generated by arc discharge and to effectively demonstrate the effects of laser welding and to achieve the penetration of the welded material. A welding method can be realized.
[0042]
In addition, when welding is performed by combining laser welding and arc welding, if the welding conditions for arc welding are conditions that cause a short-circuit transition phenomenon, plasma due to arc discharge will be extinguished during the transition to short-circuit, The maximum power can be given to the laser beam for the material.
[0043]
Therefore, even with this configuration, it is possible to realize a combined welding method of a laser and an arc that can effectively exhibit the effect of laser welding and can obtain the penetration of the material to be welded while being simple. it can.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a welding apparatus for carrying out the present invention.
FIG. 2 is an explanatory diagram of a welding state according to an embodiment of the present invention.
FIG. 3 is an explanatory diagram of a welding state in the case of arc welding alone in the prior art.
FIG. 4 is an explanatory diagram of a welding state when laser and arc welding are combined in the prior art.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Welding torch 2 Material to be welded 5 Plasma by arc discharge 6 Weld bead 7 Motor 8 Discharge electrode 9 Plasma by laser 11 Condensing mirror 12 Laser beam 13 Laser oscillator 14 Laser power supply 15 Depth of penetration 16 Laser nozzle 17 Table 18 Fixing treatment Tool 19 Filler feeding device 20 Welding power source 21 Controller

Claims (4)

In the laser and arc combined welding method of welding the workpiece by combining laser light from laser welding and arc heat from arc welding,
Welding power that irradiates the workpiece with laser light from a laser oscillator and repeats disappearance and generation of arc discharge between the workpiece and the welding torch from a welding power source. And a laser-arc combined welding method characterized in that plasma generated by arc discharge is extinguished . 2. The combined laser and arc welding method according to claim 1, wherein the welding power is in a pulse form having a pulse interval that causes a plasma generated by arc discharge to disappear. . 2. The laser / arc combined welding method according to claim 1, wherein the welding power is an alternating current having an interval sufficient to eliminate plasma generated by arc discharge . In a combined laser and arc welding apparatus that welds the workpiece by combining laser light from laser welding and arc heat from arc welding,
A laser oscillator for irradiating the workpiece with laser light;
A laser power source of the laser oscillator;
A welding power source that supplies welding power that causes arc discharge between the welding material and the torch from a welding power source;
A controller that controls the welding power source so that plasma generated by arc discharge disappears by supplying a welding power in which arc discharge repeats disappearance and generation with the workpiece.
A laser and arc composite welding apparatus characterized by comprising:

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