JP2004237326A - Narrow weld joint tungsten inert gas (tig) welding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a narrow weld joint TIG welding machine, which can improve productivity and can reduce a production cost. <P>SOLUTION: In the narrow weld joint TIG welding machine which performs welding for joining metals having a narrow weld joint, an electrode does not have a conical shape but has an eccentric shape, and the eccentric electrode melts wires while turning in the narrow weld joint. In addition, in the narrow weld joint TIG welding machine, the wires are supplied from the front and the rear of the eccentric electrode. In addition, in these two wires, the wire supplied from the front of the eccentric electrode is supplied after heating, and the wire supplied from the rear of the eccentric electrode is supplied without being preheated. Further, both of the wires supplied from the front of the eccentric electrode and the wire supplied from the rear of the eccentric electrode are supplied after heating. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a non-consumable arc welding (TIG welding) pipe made of various metal materials and a narrow groove TIG welding apparatus for large structures.
[0002]
[Prior art]
In narrow groove welding performed using a conventionally proposed non-consumable arc (TIG welding) welding method, there is a method in which a conical electrode is bent and the electrode is rotated (for example, Patent Document 1, There is a method in which a conical electrode is eccentrically rotated by a cam (for example, Patent Document 3).
[0003]
[Patent Document 1]
Patent Publication 7-276051 (Detailed Description of the Invention [0006])
[Patent Document 2]
Patent publication Hei 10-6011 (Detailed description of the invention [0006])
[Patent Document 3]
Patent Publication No. 7-108379 (Detailed description of the invention [0005])
[0004]
[Problems to be solved by the invention]
However, the prior art has a problem in the production capacity, the problem is that the thicker the plate, the larger the consumption of the inert gas and the higher the production cost, and furthermore, the direction of supply of the wire is fixed. Therefore, there is a problem that the productivity is reduced by the time required to return the welding head in the longitudinal welding due to the determination of the welding direction.
[0005]
Therefore, an object of the present invention is to provide a narrow groove TIG welding device that can increase production capacity and reduce production cost.
[0006]
[Means to solve the problem]
In order to achieve the above object, a narrow groove TIG welding device of the present invention comprises:
In a narrow groove TIG welding apparatus for joining and welding a metal having a narrow groove, the electrode is not a conical electrode but an eccentric electrode, and the eccentric electrode is rotated within the narrow groove. Melting the wire.
[0007]
In the narrow groove TIG welding apparatus, it is preferable that a wire is fed from the front and the rear of the eccentric electrode.
[0008]
It is preferable that, of the two wires, the wire fed from the front of the eccentric electrode is heated, and the wire sent from the rear is fed without preheating.
[0009]
In the two wires, it is preferable that both the wire fed from the front and the wire sent from the back of the eccentric electrode are heated and fed.
[0010]
In the narrow groove TIG welding device, the rotation angle of the eccentric electrode may be ± 45 ° to ± 90 ° depending on the combination of the width of the narrow groove and the size of the eccentric electrode. It is suitable.
[0011]
Further, in the narrow groove TIG welding apparatus, when rotating the eccentric electrode to the left and right, at both ends of the metal side wall, a current flowing simultaneously with stopping and a current flowing when moving in the opposite direction are different currents. Is preferred.
[0012]
Further, in the narrow groove TIG welding apparatus, the TIG torch holding the eccentric electrode has an inner diameter of the concentric circle larger by +1.0 to 1.8 mm than the outer diameter of the eccentric electrode, and the outer diameter is 18 A TIG torch tip shape having a conical nozzle of about 22 ° and another gas nozzle on its outer diameter side and a conical angle of 12 ° to 16 ° on its inner side, and each gap It is preferable to flow an inert gas having a different flow rate into the air.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, in TIG welding, the shape of the tungsten electrode 2 for generating the arc 1 is a conical shape of about 40 °.
[0014]
However, when the tungsten electrode 2 is rotated around the central axis 4 of the tungsten electrode in this shape, the arc 1 remains at the same position. That is, it stays at the position of the molten metal pond 3 shown in FIG.
[0015]
Therefore, in order to perform narrow welding in which the distance between the metal materials on both sides is narrow by about 6 to 12 mm by narrow groove welding, it is necessary to melt the metal walls on both sides, and it is desired to directly apply the arc 1 to the side walls.
In order to solve this problem, the tungsten electrode 2 is polished at an angle of 30 ° to 40 ° as shown in FIG. Penetration can be obtained from the central axis 4 of the electrode to 8 mm outside.
[0016]
In the present invention, a tungsten electrode polished at an angle of 30 ° to 40 ° as shown in FIG. 2 is referred to as an eccentric electrode 5.
[0017]
3A and 3B are views showing the penetration width of the eccentric electrode in the present invention, and FIG. 3A shows the eccentric electrode polished at an angle of 45 ° repeated ± 90 °, that is, rotated 180 °. FIG. 3B shows that an eccentric electrode polished at a 30 ° angle can be penetrated by ± 90 °, that is, 180 °, to form a 14mm wide penetration. It shows that it can be obtained.
[0018]
As shown in FIG. 4, when the same 180 ° rotation repeated weaving is performed in a narrow groove having a groove width of 8 mm using this method, the arc 1 can be applied to both side walls 6, 6 ′ of the metal, and sufficient melting can be performed. Can be obtained.
[0019]
FIG. 5 is a diagram showing the locus of weaving due to the rotation of the eccentric electrode. As shown in FIG. 5, the arc weaving width is adjusted by changing the rotation angle, and according to the groove width and the welding speed. It is effective to change from ± 45 ° (weaving width 90 °) to ± 90 ° (weaving width 180 °).
[0020]
FIGS. 6A and 6B are diagrams illustrating FIG. 5 more clearly. FIG. 6A shows that when the groove width is narrow (6 to 10 mm), ± 45 ° (weaving width 90 °) is used. Indicates that when the groove width is wide (12 to 14 mm), it is ± 90 ° (weaving width 180 °).
[0021]
Naturally, it is necessary to supply a welding wire to fill the groove. However, when high-speed traveling welding is performed, the molten metal pool becomes long, the cooling of the weld metal is delayed, and the surface appearance can be seen. In order to compensate for this, the problem can be solved by adopting a method of inserting a cooling wire 8 different from the front wire in order to cool the molten pool from the rear in the traveling direction as shown in FIG. In addition, it is possible not only to perform high-speed traveling welding by melting the cooling wire 8 to cool the molten metal, but also to improve the joint performance of the weld metal.
By heating the wire 7 supplied from the front in order to greatly improve the productivity, the welding speed can be greatly improved.
In addition, since the wires are supplied from both sides, the welding can be performed reciprocally in the welding direction, and the conventional return time is not required, and the production efficiency can be greatly improved. Therefore, the wire 7 and 8 sent from the front and rear are both heated and supplied to improve the welding speed, thereby improving productivity.
[0022]
In the present invention, the electrode 5 having the eccentric shape is repeatedly rotated and welded, but since the metal walls 6, 6 'on both sides are melted by stopping on both sides, there is no problem in securing the penetration. The molten metal wire 7 is supplied to the central portion and becomes the deposited metal. At this time, the molten metal pond 3 is cooled by melting the wire 7 and the depth of the molten metal pond 3 becomes shallow, and it is difficult to improve the welding speed. Therefore, it is required to supply different welding currents as shown in FIG. 8 when the motor is stopped at both ends of the rotary weaving and when welding is repeatedly performed.
It is desirable to have a higher current flow during repetitive weaving and a slightly lower current flow during both end stops. That is, when the arc 1 is directly applied to the side walls 6, 6 'when both sides are stopped, the metal side walls 6, 6' can be easily melted, so that low energy is sufficient.
[0023]
The wire supply amount also tends to be the same as the current, and needs to be controlled as shown in FIG. 7 in synchronization with the arc rotation. That is, the molten metal pond 3 is sufficiently melted with a high current so that the wire 7 is sufficiently melted when the arc 1 is directed to the side walls 6, 6 'of the metal.
As shown in FIG. 9, conventionally, when welding an initial layer having a large plate thickness by narrow groove welding, it is necessary to use an inert gas atmosphere to protect the molten metal from the atmosphere, and a large amount of (80 to 100 L / min) of an inert gas (argon or helium) is flowed. However, the inert gas is very expensive and raises the welding cost.
[0024]
In order to solve this problem, a TIG torch having a structure shown in FIG. 10 was adopted.
That is, in the narrow groove TIG welding device, the TIG torch 9 holding the eccentric electrode 5 has a concentric inner diameter larger by +1.0 to 1.8 mm (A in the figure) than the eccentric electrode outer diameter, Further, the gas nozzle has a conical gas nozzle having an outer diameter of 18 ° to 22 °, most preferably 20 ° (1 in the figure), and further has another gas nozzle 11 on the outer diameter side thereof, and has an inner cone. It has a TIG torch tip shape with an angle of 12 ° to 16 °, most preferably 14 ° (2 in the figure), and has a structure in which an insoluble gas having a different flow rate flows through each gap.
The center gas flows through the conical gas nozzle 10, and the shielding gas flows through the other gas nozzle 11.
[0025]
When the center gas is flowed at a flow rate of 5 L / min through the conical gas nozzle 10 and the shield gas is flowed through the outer gas nozzle 11 at a flow rate of 15 L / min, the outer cone angle of the conical gas nozzle 10 and the inner surface angle of the other gas nozzle 11 It is clear from the measurement results shown in FIG. 10 that the suction effect of the shielding gas (argon) occurs due to the combination of 2, and the atmospheric oxygen concentration in the initial layer portion of the thick plate welding by narrow groove welding is set to 30 PPM or less. . That is, since the width of the conical gas nozzle 10 is narrow, the flow velocity is high even if the amount of the center gas is small, so that the shield gas is pulled by the flow velocity of the center gas and the shield gas is drawn in (enters). )That's what it means.
As a result, the amount of the inert gas conventionally supplied at 80 to 100 L / min can be reduced to 1/5 to 1/6, and the effect on cost reduction is enormous.
[0026]
【The invention's effect】
Since the present invention has the above configuration, it is possible to increase production capacity and reduce production cost in narrow groove TIG welding.
[Brief description of the drawings]
FIG. 1 is a view showing a conventional TIG welding electrode.
FIG. 2 is a view showing an eccentric electrode according to the present invention.
FIG. 3A is a diagram showing the penetration width of an eccentric electrode polished at an angle of 45 ° according to the present invention.
FIG. 3B is a diagram showing the penetration width of an eccentric electrode polished at an angle of 30 ° according to the present invention.
FIG. 4 is a view showing rotation of an eccentric electrode in a narrow groove according to the present invention.
FIG. 5 is a diagram showing a locus of weaving due to rotation of an eccentric electrode of the present invention.
FIG. 6A is a view showing a case where a groove width of the present invention is narrow.
FIG. 6B is a diagram showing a case where the groove width of the present invention is wide.
FIG. 7 is a diagram showing the feeding of the cooling wire of the present invention.
FIG. 8 is a view showing a rotary welding control system for an eccentric electrode according to the present invention.
FIG. 9 is a view showing a gas shield in conventional narrow groove welding.
FIG. 10 is a view showing two types of gas shields in narrow groove welding according to the present invention.
FIG. 11 is a diagram showing measured values of oxygen concentration according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Arc 2 Tungsten electrode 3 Molten metal pond 4 Central axis 5 Eccentric electrode 6, 6 'Metal wall 7 Wire from the front 8 Wire from the back 9 TIG torch 10 Conical gas nozzle 11 Another gas nozzle

Claims (7)

In a narrow groove TIG welding apparatus for joining and welding a metal having a narrow groove, the electrode is not a conical electrode but an eccentric electrode, and the eccentric electrode is rotated within the narrow groove. A narrow groove TIG welding device for melting a wire. The narrow groove TIG welding device according to claim 1, wherein in the narrow groove TIG welding device, a wire is fed from a front side and a rear side of the eccentric electrode. 3. The narrow opening according to claim 2, wherein in the two wires, the wire fed from the front of the eccentric electrode is heated, and the wire fed from the rear is fed without preheating. 4. Tip TIG welding equipment. 3. The narrow wire according to claim 2, wherein, of the two wires, both the wire fed from the front and the wire fed from the back of the eccentric electrode are heated and fed. 4. Groove TIG welding equipment. In the narrow groove TIG welding device, the rotation angle of the eccentric electrode is ± 45 ° to ± 90 ° by a combination of the width of the narrow groove and the size of the eccentric electrode. The narrow groove TIG welding device according to claim 1. In the narrow groove TIG welding device, when rotating the eccentric electrode to the left and right, at both ends of the metal side wall, the current flowing when stopping and the current flowing when moving in the opposite direction are different currents. The narrow groove TIG welding apparatus according to any one of claims 1 to 5, wherein: In the narrow groove TIG welding apparatus, the TIG torch holding the eccentric electrode has an inner diameter of the concentric circle larger by +1.0 to 1.8 mm than the outer diameter of the eccentric electrode, and the outer diameter is 18 ° to It has a 22 ° conical nozzle, has another gas nozzle on its outer diameter side, has a TIG torch tip shape with a conical angle of 12 ° to 16 ° inside, and has a flow rate in each space. The narrow groove TIG welding apparatus according to any one of claims 1 to 6, wherein an inert gas having a different width is supplied.

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