JP3211318B2 - Torch for TIG arc welding and pulse TIG arc welding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a TIG for improving the efficiency of a welding operation and obtaining a good and high-quality weld bead.
The present invention relates to an arc welding torch and a pulse TIG arc welding method.

[0002]

2. Description of the Related Art Generally, a TI which is supplied by supplying a welding wire is used.
In the G arc welding, for example, as shown in FIG. 4, the non-consumable electrode 1 'is surrounded by a gas nozzle 5 and the non-consumable electrode 1' is surrounded by an atmosphere of a shield gas 8 supplied from inside the gas nozzle 5. An arc 9 is generated by applying a voltage between the welding power supply 7 and the workpiece 11. A welding wire guide 21 is provided outside the gas nozzle 5, and the consumable welding wire 3 is supplied from the welding wire guide 21 into the arc 9 by the wire feeding device 4 to perform welding.
Further, as shown in FIG. 5, a TIG arc welding torch provided with a gas nozzle 5 so as to surround the non-consumable electrode 1 'and the welding wire guide 21 has also been proposed. Furthermore, as shown in FIG. 6, a non-consumable electrode 1 'is provided with an axial through hole 101, and an axial through hole 201 made of a heat-resistant electrical insulating material is provided inside the through hole 101. The insulating member 2 is provided, and welding is performed by supplying the welding wire 3 from the through hole 201 of the insulating member 2 by the wire feeding device 4.

[0003]

However, in the apparatus shown in FIG. 4, since the welding wire guide 21 is provided outside the gas nozzle 5, the apparatus becomes large, and is applicable to welding of narrow portions. Can not. Further, since the welding wire 3 is inserted from the side of the gas nozzle 5, the flow of the shield gas 8 supplied from the gas nozzle 5 is disturbed, and entrainment of the atmosphere occurs, and welding defects such as blowholes occur. Is likely to occur. In the apparatus shown in FIG. 5, since the non-consumable electrode 1 'and the welding wire guide 21 are provided independently of each other inside the gas nozzle 5, the diameter of the gas nozzle 5 increases, and welding of a narrow portion is performed. Could not be applied to Further, in the device shown in FIG.
The arc 9 generated at the tip of the electrode 1 'creeps up above the non-consumable electrode 1', and the arc 9 generated from the cylindrical electrode 1 '.
State becomes unstable. In addition, since the insulating member 2 included in the non-consumable electrode 1 'is overheated, there is a problem that the insulating member 2 is severely damaged. Therefore, an object of the present invention is to
A small TIG that can be used for welding narrow spaces, with stable arc obtained and no welding defects such as blowholes.
An object of the present invention is to provide an arc welding torch and a pulse TIG arc welding method.

[0004]

According to a first aspect of the present invention, there is provided a TIG arc welding torch, wherein the non-consumable electrode is provided with an axial through hole.
01 and a cylindrical through hole 201 in the axial direction.
A cylindrical insulating member 2 having a through hole in the non-consumable electrode 1
In the TIG arc welding torch, a gas nozzle surrounding the insulating member and the non-consumable electrode is disposed in the torch body and a shield gas is supplied into the nozzle. The tip of the non-consumable electrode protrudes in a direction perpendicular to the axis of the welding wire, on the one side perpendicular to the axis of the welding wire, in a direction away from the welding wire and in the direction of feed of the welding wire. A TIG arc welding tor formed by forming a stepped portion having a smaller cross-sectional area on the front end side than the base side by the orthogonal plane portion, and sharpening the front end of the protruding end portion.
Ji.

[0005] The torch for TIG arc welding according to claim 2 is
TIG in which non-consumable electrodes enclose an insulating member concentrically
It is a torch for arc welding.

According to a third aspect of the present invention, there is provided a TIG arc welding torch,
A TIG arc welding torch in which the free end of the insulating member is disposed at a position on the welding wire feeding direction side of the step of the non-consumable electrode.

According to a fourth aspect of the present invention, there is provided a pulsed TIG arc welding method according to any one of the first to third aspects, wherein the pulse frequency is 5 Hz to 500 Hz. This is a pulse TIG arc welding method in which welding is performed by passing an electric current.

[0008]

The operation of the pulse TIG arc welding method according to the present invention will be described below with reference to FIG. The figure shows
In the pulse TIG arc welding method of the present invention, the pulse frequency F [Hz] (horizontal axis) when a pulse current is applied between the non-consumable electrode 1 and the workpiece 11 shown in FIG. The molten ball 10 just before the molten ball 3a moves from the welding wire tip 3a to the workpiece 11
FIG. 6 is a diagram showing a relationship with a diameter D [mm] (vertical axis). The welding conditions are as follows. YGW-12 welding wire 3
The wire diameter of the welding wire 3 is 1 mm and the feeding speed of the welding wire 3 is 80 cm /
The pulse current is set to 300 A, the base current is set to 100 A, the average welding current is set to 200 A, and the welding speed is set to 20 cm / min. As shown in the figure, the diameter D of the molten ball 10 at the welding wire tip 3a
Is 2 [m] when the pulse frequency F is less than 5 [Hz].
m] or more and more than twice the diameter of the welding wire 3 [1 mm], the molten ball 10 is not consumed when welding is performed for a long time because the welding wire 3 is transferred to the workpiece 11. It is easy to come into contact with the conductive electrode 1. Also, at a pulse frequency F of less than 5 [Hz], it can be confirmed that the cycle in which the molten sphere 10 formed at the welding wire tip 3a falls by its own weight is larger than the cycle of the arc vibration obtained by the pulse. ing. Further, when the pulse frequency F is 5
Even when the frequency exceeds 00 [Hz], the diameter D of the molten ball 10 at the welding wire tip 3a is such that the pulse frequency F is 5 [H].
z], the diameter of the welding sphere 3 has reached twice as large as the diameter of the welding wire 3, and the diameter of the molten sphere 10 is almost the same as that without the pulse. Therefore, when the pulse frequency F is less than 5 [Hz] or more than 500 [Hz], vibration is not obtained to such an extent that the molten ball 10 of the welding wire tip 3a is separated from the welding wire tip 3a. Can be confirmed. When the pulse frequency F is set to 5 Hz or more and 500 Hz or less, the molten ball 10 at the welding wire tip 3a can be easily detached from the welding wire tip 3a, and the molten ball 10 becomes non-melting. Since there is no welding to the consumable electrode 1, a stable welding method can be performed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments. In FIG. 1, reference numeral 1 denotes a cylindrical non-consumable electrode having an axial through hole 101 made of, for example, tungsten or thorium oxide, cerium oxide, or tungsten containing lanthanum oxide, and 2 denotes a heat-resistant electrically insulating material, for example, A cylindrical insulating member having an axial through-hole 201 made of crystalline alumina. The insulating member 2 is provided in the through-hole 101 of the non-consumable electrode 1. Reference numeral 3 denotes a consumable welding wire, which is fed by the wire feeder 4 through the through hole 201 of the insulating member 2 in the direction of the workpiece 11, that is, in the Z1 direction. Reference numeral 5 denotes a gas nozzle provided on the torch main body 6 so as to surround the non-consumable electrode 1 and the insulating member 2. As shown in FIGS. 2 (A) to 2 (C), the non-consumable electrode 1 which encloses the insulating member 2 concentrically has a notch in the X2 direction and a welding wire 3 in the X1 direction. A spaced protruding end 102 is formed.
On the Z2 direction side is a notched semicircular portion 10 cut out in the X2 direction.
3 are formed. Protruding end portion 102 and cutout semicircular portion 10
A first step portion 104 is formed at the boundary with No. 3, and a second step portion 105 is formed at the boundary between the cutout semicircular portion 103 and the base. The tip 106 of the protruding end 102 is pointed. The free end 202 of the insulating member 2 is connected to the non-consumable electrode 1.
Of the welding wire 3 with respect to the first step portion 104 in the feeding direction,
That is, it is disposed at the position on the Z1 direction side. With the above configuration, the shield gas 8 supplied from inside the gas nozzle 5
A voltage is applied between the non-consumable electrode 1 and the workpiece 11 by the welding power supply device 7 through the power supply member or directly in the atmosphere, and the arc is applied from the tip 106 of the non-consumable electrode 1. 9 is generated, and welding is performed while the welding wire 3 fed by the wire feeding device 4 is guided by the insulating member 2. The free end 202 of the insulating member 2 is connected to the first step 1 of the non-consumable electrode 1.
Since the welding wire 3 is disposed at a position on the feed direction side of the welding wire 3, that is, on the Z1 direction side, the target point of the welding wire 3 is stabilized, and good welding can be obtained. The free end 202 of the insulating member 2 protrudes in the Z1 direction, and the tip of the insulating member 2 is
Since it is more exposed, the insulating member 2 is efficiently cooled by the shield gas 8. Furthermore, the shield gas 8 generated by the first and second steps 104 and 105
The cooling effect is greater due to the eddy current. The protruding end portion 1 of the non-consumable electrode 1 on the Z1 direction side of the first step portion 104
02 is formed to be smaller than the first step portion 104 in the Z2 direction side.
Since the current density at 02 is high, the arc generation point is concentrated on the protruding end portion 102, and does not crawl upward, but becomes stable. In addition, if the second step 105 is provided by the cutout semicircular part 103, it is preferable in terms of the cooling effect, but the second step 105 can be omitted regardless of this.

FIGS. 3A to 3C are views showing the main parts of a second embodiment of the present invention, and the same components as those in FIG. 2 are denoted by the same reference numerals. In this embodiment, the non-consumable electrode 1
For example, a flat plate of tungsten or thorium oxide, cerium oxide or tungsten containing lanthanum oxide is cut out so that the tip side has a smaller cross-sectional area than the base side to form a protruding end portion 102, steps 104, 104, and a protruding end portion. The tip 106 of 102 is sharpened. Reference numerals 12 and 12 denote couplers for integrating the non-consumable electrode 1 and the insulating member 2. 2 and 3, the free end 202 of the insulating member 2 is shown.
Is disposed on the side of the welding wire 3 in the feed direction, that is, on the Z1 direction side of the step 104 of the non-consumable electrode 1, but the free end 202 of the insulating member 2 is connected to the first step. Part 104
And can be arranged at the same level. As shown in FIGS. 1 and 2, if the non-consumable electrode 1 and the insulating member 2 are coaxially circular in cross section, the cross-sectional area of the torch can be minimized. The electrode 1 and the insulating member 2 may be appropriately rectangular or polygonal, respectively.

With the above structure, the arc generation point is concentrated on the tip end portion 106 of the non-consumable electrode 1 having a high current density, and does not creep upward, that is, in the Z2 direction, and becomes stable. Also, since no air entrainment occurs in the welded portion, no welding defects such as blowholes occur,
Since the torch can be made small, it can be applied to welding of narrow portions.

FIG. 8 shows, for comparison with the prior art, the welding method of the present invention in which a pulse current of a predetermined frequency indicated by a solid line A is applied and the conventional welding method in which a pulse current indicated by a dotted line Z is not applied. It is a figure which shows the relationship between the electric current I [A] (horizontal axis) and the maximum value V [cm / min] (vertical axis) of the welding wire feeding speed. In the same figure, the welding method according to the present invention, in which vibration by an arc can be obtained by applying a pulse current, is about 1.2 to 1.5 times as large as the conventional welding method in which no pulse current is applied. The maximum value of the wire feeding speed is obtained. Thereby, in the welding method of the present invention, the efficiency of the welding speed can be improved.

FIGS. 9 and 10 are views showing the appearance of a weld bead and the penetration shape of the weld bead when mild steel is used for comparison with the conventional steel. FIG. 9 (Z) and FIG.
0 (Z) is the case where the conventional welding method in which the pulse current is not applied is performed, and FIGS. 9 (A) and 10 (A) are the cases where the welding method of the present invention in which the pulse current is applied is performed. . As shown in FIG. 9 (Z), in the conventional welding method in which no pulse current is applied, the detachment of the molten ball 10 formed at the welding wire tip 3a from the welding wire tip 3a is due to the weight of the molten ball 10. In addition, the transition of the molten sphere 10 from the welding wire tip 3a to the workpiece 11 is not stable, the weld bead is meandering, and a beautiful weld bead shape is not obtained. In addition, as shown in FIG. 10 (Z), in the conventional welding method in which a pulse current is not supplied, the arc 9 does not concentrate on the work 11 because the welding method is not stable. No penetration has been obtained. In contrast to the conventional welding method described above, in the welding method of the present invention in which a pulse current is applied, as shown in FIG. 9A, the vibration of the arc 9 due to the pulse causes the detachment of the molten ball 10 from the welding wire 3. A stable welding method can be performed to promote the welding, and a beautiful weld bead shape can be obtained. In addition, as shown in FIG. 10A, in the welding method of the present invention in which a pulse current is applied, the welding method is stable, and the welding method in which the arc 9 is concentrated on the workpiece 11 is performed. Therefore, a sufficient weld bead shape with deep penetration is obtained.

[0014]

As described above, according to the present invention, a stable arc is obtained, and no welding defects such as blowholes are generated. -A welding torch can be realized. Furthermore, the pulse TIG arc welding method of the present invention generates an arc vibration and promotes detachment of the molten ball at the tip of the welding wire, so that the welding wire does not come into contact with the non-consumable electrode during welding. In addition, a beautiful weld bead shape with a deep penetration that does not meander the weld bead can be obtained. Further, since the welding wire feed rate can be increased, there is an effect that the welding efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional front view showing an embodiment of the present invention.

FIGS. 2A and 2B are views showing main parts of FIG. 1, wherein FIG. 2A is a front view, FIG. 2B is a right side view of FIG. 2A, and FIG.
FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a diagram showing a main part of a second embodiment, and FIG.
(A) is a front view, FIG. (B) is a left side view of FIG.
FIG. 2C is a cross-sectional view of the same as FIG. 1A.

FIG. 4 is a longitudinal sectional view, partially cut away, showing a conventional example.

FIG. 5 is a longitudinal sectional view of another conventional example with a part cut away.

FIG. 6 is a longitudinal sectional view, partially cut away, showing still another conventional example.

FIG. 7 is a pulse frequency F [Hz] when a pulse current is applied between the non-consumable electrode 1 and the workpiece 11 in the pulse TIG arc welding method of the present invention.
It is a figure which shows the relationship between (the horizontal axis) and the diameter D [mm] (vertical axis) of the molten ball 10 just before the molten ball 10 of the welding wire tip 3a shifts from the welding wire tip 3a to the workpiece 11. .

FIG. 8 shows the welding current I [A] (horizontal axis) and the welding current of the present invention in which the pulse indicated by the solid line A is set and the conventional welding method in which the pulse indicated by the dotted line Z is not set. It is a figure which shows the relationship with the maximum value V [cm / min] (vertical axis) of the wire feeding speed.

FIG. 9 is a view showing the appearance of a weld bead when mild steel is used, and FIG. 9 (Z) shows a case where a conventional welding method without setting a pulse is performed; () Shows a case where the welding method of the present invention for setting a pulse is performed.

FIG. 10 is a view showing a penetration shape of a weld bead when mild steel is used. FIG. 10 (Z) shows a case where a conventional welding method without setting a pulse is performed. FIG. 7A shows a case where the welding method of the present invention for setting a pulse is performed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Non-consumable electrode 2 Insulating member 3 Welding wire 3a Welding wire tip 4 Wire feeding device 5 Gas nozzle 6 Torch main body 7 Welding power supply 8 Shielding gas 9 Arc 10 Melting sphere 11 Workpiece 104 First step F Pulse frequency D The diameter of the molten ball 10 V The maximum value of the welding wire feeding speed I The welding current

Continuation of the front page (72) Inventor Hidetaka Nohara 2-1-1-11 Tagawa, Yodogawa-ku, Osaka-shi Daihen Co., Ltd. (56) References JP-A-59-130686 (JP, A) JP-A-59-202177 (JP) , A) Japanese Utility Model Showa 48-112822 (JP, U) Japanese Utility Model Showa 61-10851 (JP, Y2) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23K 9/29 B23K 9/167

Claims (4)

(57) [Claims] The non-consumable electrode has an axial through hole.
Cylinder with a through hole in the axial direction.
The edge member, preparative gas nozzle surrounding said insulating member and said non-consumable electrode while disposed in the through hole of the non-consumable electrode - disposed in Ji body, the interior of the nozzle - the Rudogasu In the TIG arc welding torch to be supplied,
The non-consumable electrode has a tip portion protruding in one direction perpendicular to the axis of the welding wire, spaced apart from the welding wire, and protruding in the feeding direction of the welding wire. A TIG arc welding torch formed by forming a stepped portion having a smaller cross-sectional area on the distal end side than the base side by the flat surface portion, and sharpening the distal end of the protruding end portion. 2. The torch for TIG arc welding according to claim 1, wherein the non-consumable electrode includes the insulating member concentrically. 3. The TIG arc welding according to claim 1, wherein the free end of the insulating member is disposed at a position closer to the welding wire feeding direction than the step of the non-consumable electrode. Torch for 4. The TI according to claim 1, wherein:
In a TIG arc welding method performed using a torch for G arc welding, a pulse TIG arc welding method in which a pulse welding current having a pulse frequency of 5 Hz or more and 500 Hz or less is applied to perform welding.