JPH11138269A - Tig welding equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a satisfactory weld zone whose weld bead has a smooth, uniform and beautiful surface by forming a curved tungsten electrode as one to be attached to the tip end of a welding torch. SOLUTION: A welding torch 1 having a nozzle guide 7 connected with a guide fixing part 9 is inclined obliquely downward against an upright side plate 13, fastened with a torch fixing part 8, and disposed in a motor-driven truck 17 that is engaged with a traveling rail 11. To the tip end of the welding torch 1, a curved tungsten electrode 20 is attached. In addition, at the tip end of the welding torch 1, a cylindrical seal cover 21 is installed, covering around the curved tungsten electrode 20 as well as guiding shielding gases to be supplied so that they reach the weld zone in the tip end direction of the electrode. This seal cover 21 is so formed that it affects no welding operation even if the welding torch 1 is lowered to the bottom, with the lower end of the seal cover 21 hitting the upper face of the bottom plate 12, and that automatic welding can start from this lowest position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a tungsten alloy.
The present invention relates to a TIG welding apparatus for performing inert gas arc welding (hereinafter referred to as TIG welding).

[0002]

2. Description of the Related Art In TIG welding, an inert gas such as argon or helium which does not react with metals even at a high temperature, that is, an inert gas (hereinafter referred to as a shielding gas) flows from a nozzle of a welding torch, and a tungsten rod is inserted in the gas atmosphere. This is a method in which an arc is generated as an electrode between a portion to be welded and a welding rod (wire) is melted by this arc to perform welding. The tungsten electrode rod is supported by projecting about several millimeters from the tip of the nozzle of the welding torch, and the welding current is transmitted to the electrode through a water-cooled or air-cooled support bracket.
Further, the shielding gas flows out little by little from the nozzle at the tip of the welding torch to maintain the welded portion in an inert gas atmosphere.

[0003] There are three types of TIG welding methods: manual, semi-automatic, and automatic. The TIG welding device includes a welding torch, an arc welding machine, a control device, a shielding gas supply device, a cooling device, and the like. Manual TIG welding is a method of manually supplying the wire and moving the welding torch, and semi-automatic TIG welding is a method of manually moving the welding torch and automatically supplying the wire at a constant speed. TIG welding is a method in which both supply of the wire and movement of the welding torch are performed automatically at a constant speed. In an automatic welding device, a welding torch, a wire supply device, a control device, and the like are mounted on one electric bogie and move, or they are fixed and a work to be welded moves. I have.

[0004] Using a conventional automatic TIG welding device,
The case where a vertical joint near the bottom of the storage tank side plate is welded will be described with reference to FIGS. 3 and 4. 3 and 4 show the vicinity of a welded portion having a T-shaped cross section in which the bottom plate 12 and the side plate 13 of the storage tank are orthogonal to each other. The side plate 13 is erected on the bottom plate 12 and the side plates 13
Are welded upward from the lower end and the longitudinal joint 16 is welded.

A welding torch 1 of a TIG welding apparatus is generally JIS Z
Tungsten electrode 2 for TIG welding specified in 3233
An arc is generated by applying a discharge voltage between the tungsten electrode 2 and the portion to be welded, an arc current is supplied, a wire 5 of a welding material is fed to the arc, and the wire 5 is heated by the arc. The welding portion is welded while melting the metal. In general, the nozzle at the tip of the welding torch 1 is provided with a JI so as to cover the periphery of the tungsten electrode 2.
A shield cup for introducing an inert gas such as argon gas specified in S K1105 is provided. The illustration example is
This figure shows a case where a double seal cup composed of the outer shield cup 3 and the inner shield cup 4 is attached to improve the gas shielding performance. The surfaces of the tungsten electrode 2, the wire 5, and the molten portion are covered with an inert gas supplied at a controlled flow rate from the inner and outer seal cups 3 and 4, and the electrode and the welded portion are oxidized at a high temperature by oxygen in the air, or The high-temperature nitriding due to nitrogen in the air is prevented from being altered.

As shown in FIG. 3, the welding torch 1 is engaged with an electric trolley 17 at a torch fixing portion 8, and the trolley 17 is fixed so as to be able to move up and down along the traveling rail 11. This automatic TIG welding apparatus detects and adjusts the distance from the electrode tip of the welding torch 1 to the welded portion, generates an appropriate arc between the welded portion and the joint of the side plate 13, and generates the generated arc. The wire 5 is automatically fed to the section and the weaving for oscillating the welding torch 1 so as to further widen the welding range is repeated, and the electric bogie 17 automatically moves the entire welding torch 1 and the wire supply section while moving. It is formed to perform welding.

Reference numeral 6 denotes a nozzle tip at the tip of the supply portion of the wire 5, and 7 denotes a nozzle guide for guiding the supply wire 5.
The nozzle guide 7 is fixed at a fixed angle with the guide fixing portion 9 as a support axis, and the tip of the wire 5 is further moved by a wire position adjuster 10 between the tip of the electrode where the arc is generated and the portion to be welded. It is formed to guide. Although not shown, a bogie 17 includes a wire reel on which the fed wire 5 is wound and a wire feeding device for continuously feeding the wire 5 from the wire reel to the nozzle guide 7.
It is provided in.

[0008]

As shown in FIG. 3,
The conventional automatic TIG welding device is configured such that when the welding torch 1 is installed so as to face the side plate 13 at a right angle, a welded portion of the side plate 13 near an orthogonal portion between the bottom plate 12 and the side plate 13, The range L from the start end of the joint portion 16 cannot be welded because the lower half of the outer shield cup 3 and the torch fixing portion 8 protruding below the tungsten electrode 2 hit the upper surface of the bottom plate 12 and cannot be lowered. A condition arises. Range L from the starting end where this welding is not possible
Varies depending on the size, type, type, etc. of the welding device, but is about 5 cm to 50 cm. Such welding of the range L from the start end is as follows.
Conventionally, in general, rather than automatic TIG welding, complicated welding methods such as a method of performing manual welding using a covered arc welding rod and a method of performing inert gas arc welding using a handheld welding torch have been adopted. In some cases, the side plate 13 is floated by a jack or the like by a distance corresponding to the range L from the start end, welding is performed using automatic TIG welding, and the vertical joint 16 is welded in a predetermined range, and then the jack is lowered. Extensive construction methods, such as making it work, were also considered.

Therefore, in order to weld the range L from the start end, instead of the complicated and laborious welding method or the large-scale welding method as described above, a welding torch 1 as shown by a solid line in FIG. Automatic welding is performed in a state in which the welding torch 1 is tilted obliquely downward, and automatic welding is performed while the welding torch 1 is tilted downward and obliquely downward. After welding the range L from the start end by these methods, as shown by the dashed line in FIG. 4, the automatic torch welding apparatus is moved upward while the welding torch 1 is opposed in a right angle direction. Thus, welding of the vertical joint 16 was performed. The latter welding method of performing automatic welding while rotating the welding torch 1 is performed by rotating an automatic TIG welding apparatus upward around a rotating support shaft 15 by an electric motor 14 so as to cover a range from a starting end. L is welded, and the welding torch 1 is
In this method, an automatic TIG welding device is moved up along the traveling rail 11 to perform automatic welding after a horizontal state is formed at substantially a right angle.

[0010] However, as shown in FIG.
The method in which welding is performed in a state in which the welding torch 1 is inclined obliquely downward and the welding is performed by rotating the welding torch 1 upward in a state in which the welding is performed at a fixed angle with the Since the direction of the shield cups 3 and 4 does not face the side plate 13 and the vertical joint 16 at a right angle but faces obliquely downward and largely obliquely with respect to the horizontal, the arc at the tip of the tungsten electrode 2 is oblique. The direction of the arc becomes longer and the arc becomes longer and unstable, making it difficult to generate a steady fine and short arc.The molten metal is pushed out of the molten pool by the blast from the arc, causing dents or swelling. The side plate 13,
In some cases, it was not possible to form a uniform weld at the groove between the 13 joints, and it was difficult to obtain a uniform and beautiful weld of the vertical joint 16 having a smooth and uniform surface shape. In addition, the inert shielding gas diffuses obliquely downward, so that the gas shield may be insufficient and a good welded portion may not be obtained, and there is also a problem that gas loss occurs.

Further, in the method of performing the automatic welding by rotating the welding torch 1 upward from a state where the welding torch 1 is inclined obliquely downward, the rotation driving device including the electric motor 14 and the rotating support shaft 15 is complicated and large-scale. In addition, since the angle and length of the arc and the wire feed angle change due to the change in the inclination angle, the arc length is kept constant, and the welding position is maintained properly by keeping the wire supply position and supply amount appropriate. The control performed was complicated and difficult.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems of the prior art, and provides a TIG welding apparatus which can obtain a good welded portion from the vicinity of the starting end of a portion to be welded and has a good work efficiency. To provide.

[0013]

According to the present invention, there is provided a TIG welding apparatus in which a tungsten electrode attached to a tip of a welding torch of a TIG welding apparatus is formed as a curved tungsten electrode.

Further, the curved tungsten electrode is formed by providing a curved portion on the electrode tip side and providing a straight portion at the tip of the curved portion.

Further, a cylindrical seal cover formed so as to cover around the curved tungsten electrode is provided at the tip of the welding torch.

The welding torch to which the curved tungsten electrode is attached is inclined obliquely downward with respect to the longitudinal joint of the storage tank side plate, and the tip of the curved tungsten electrode is inclined with respect to the longitudinal joint. Are made to face each other at an angle close to a right angle, and are automatically welded while being moved by a truck provided along the longitudinal joint portion.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A TIG welding apparatus according to the present invention will be described in detail based on an embodiment shown in FIGS. FIG. 1 shows a vertical joint portion 16 in a case where butt-welding portions to be welded of side plates 13, 13 erected perpendicularly to a bottom plate 12 of a storage tank are arranged along a traveling rail 11 upward from a lower end portion. The figure shows a state in which automatic welding is performed while moving with the electric carriage 17, a part of which is omitted and a part is a sectional view. FIG. 2 is an enlarged schematic cross-sectional view showing the vicinity of the distal end of the welding torch 1 of FIG.

As shown in FIG. 1, in the TIG welding apparatus according to the present invention, the welding torch 1 having the nozzle guide 7 connected by the guide fixing portion 9 is inclined obliquely downward with respect to the upright side plate 13. It is fixed by a torch fixing part 8 and is mounted on an electric bogie 17 engaged with the traveling rail 11. A curved tungsten electrode 20 is attached to the tip of the welding torch 1. A cylindrical seal cover for guiding the shielding gas supplied to the distal end of the welding torch 1 so as to cover around the curved tungsten electrode 20 and to allow the shielding gas to reach the welded portion in the distal direction. 21 is installed.

When the welding torch 1 is attached in such a manner that the welding torch 1 is lowered to the lowermost position, the tip of the curved tungsten electrode 20 is positioned in the vertical direction between the welded portions of the side plates 13, 13. The joint portion 16 is lowered to the required welding start position to be in the vicinity of the lowermost starting end, that is, a position close to the bottom plate upper surface by about 2 to 5 mm. Thus, the automatic operation from the position very close to the bottom plate 12 upper surface is performed. It is possible to start welding. In addition, even when the welding torch 1 is lowered to the lowermost position and the lower end of the seal cover 21 hits the upper surface of the bottom plate 12, automatic welding from the lowermost position is started without any trouble in the welding operation. It is formed so that it can be done.

As shown in FIG. 2, the welding torch 1 is installed at a predetermined inclination angle X with respect to the surface of the side plate 13, for example, at an angle of about 30 degrees from a horizontal direction to an obliquely downward direction.
A straight portion 20B of the curved tungsten electrode 20 composed of a curved portion 20A that bends and a straight portion 20B at the tip thereof is inclined at an angle Y close to a right angle to the surface of the side plate 13, preferably inclined slightly upward, For example, it is attached so as to be inclined upward from horizontal by about 5 to 10 degrees. When the welding torch 1 is inclined and installed by changing the inclination angle X of the welding torch 1 to about 10 degrees to 60 degrees, the curved tungsten electrode 20 is manufactured by deforming the bending degree of the curved portion 20A in the middle. The inclination angle Y of the linear portion 20B is set to the preferable angle of about 5 to 10 degrees. In addition, the inclination angle Y is not limited to the preferable angle of 5 degrees to 10 degrees, but the groove shape of the welded portion,
Depending on the welding conditions, etc., downward 1
The inclination angle may be set so as to be approximately a right angle, that is, in the range of 5 degrees to 15 degrees upward.

As shown in FIGS. 1 and 2, the tip of the curved tungsten electrode 20 of the welding torch 1 formed as described above is inclined obliquely upward from horizontal, which always faces the side plate 13 at right angles. Since it moves upward while maintaining Y and continues automatic welding, an arc is generated at the shortest distance from the surface of the welded part, so the arc is short and fine and stable, and the fused part is forced by the blast of the arc It is not flushed down and does not hang down. In addition, the direction of the arc directed obliquely upward and the movement of the ascending welds cause the melted parts to be stacked on average so that the melted parts are pushed up somewhat, so that the bead shape does not dent or rise on the surface. , And a good weld can be obtained.

The curved tungsten electrode 20 is made of JIS Z3
Use a tungsten wire rod with a diameter of about 0.5 mm to 10 mm and a total length of about 50 mm to 150 mm of a normal tungsten electrode rod for TIG welding as specified in 233, and a welding torch. The side to be gripped at 1 is formed in a straight line, and the side opposite to the side to be gripped is a curved electrode part having a length of about 5 mm to 100 mm. The electrode portion has a curved portion 20A having a length M, for example, 5 mm to 50 mm.
The outermost peripheral edge of the curved portion is preferably formed so as not to protrude outward from the extension of the inner shield cup 4 at the end of the straight portion 20B having a length N. For example, at about 1 mm to 50 mm, it is formed so as to be inclined at the inclination angle Y and extended.

The curved tungsten electrode 20 in which the length N of the linear portion 20B at the distal end of the curved portion 20A is relatively long, for example, about 10 mm or more, is suitable for an electrode whose consumption is relatively large. When the tip is worn out and deformed round, the tip is polished and sharpened to regenerate and use it so that an arc can be generated satisfactorily. The polishing of the linear portion 20B is straight and easy to perform, and automatic polishing is also possible. In addition, the straight part 20B which is polished and sharpened
Can be repeatedly used in a state in which the angle perpendicular to the surface of the weld is maintained and the arc can be satisfactorily generated, so that the curved tungsten electrode 20 excellent in economy can be obtained. In addition, this curved tungsten electrode 20
If it is manufactured by hot bending that bends in a heated state, even if it is a linear tungsten material that is not suitable for bending, it can be economically manufactured by efficiently bending it to a predetermined shape without bending or breakage. it can.

The seal cover 21 formed so as to cover the curved tungsten electrode 20 is made of a highly heat-resistant material such as a thin aluminum plate, a heat-resistant glass fiber material, or a ceramic molding material. A detachable structure formed on the outer peripheral portion of the existing outer shield cup 3 so as to be formed into a curved cylindrical shape conforming to the shape of the curved tungsten electrode 20 or a cylindrical shape of a deformed curved plate so as to guide and guide the supplied shielding gas. Attach to In addition, welding torch 1
When the seal cover 21 is newly manufactured, the seal cover 21 is made of the same material as the outer shield cup 3 and the outer shield cup 3 is made of the same material.
May be integrally formed with the outer shield cup 3 by extending the inner diameter of the outer shield cup 3 as it is, or by extending the inner diameter of the outer shield cup 3 while gradually increasing the inner diameter. The shape of the seal cover 21 is preferably a curved cylindrical shape following the shape of the curved electrode rod, but may be an enlarged trumpet shape or a shape obtained by extending a cylinder. When the welding torch 1 is lowered to the position where it comes into contact with the upper surface of the bottom plate 12, the lower end of the seal cover 21 is slightly curved upward and inward so as not to disturb the start of welding. The directional joint 16 is formed so that automatic welding can be started without any trouble from the vicinity of the start end of the lowermost end, that is, the position very close to the upper surface of the bottom plate 12.

The shield gas supplied from the inner and outer shield cups 3 and 4 by the seal cover 21 formed as described above allows the bent portion 20A and the straight portion 20B to be bent even if the bent tungsten electrode 20 is bent and formed long. The surrounding area is always sealed with an inert gas and is isolated from the outside air, so that deterioration of the electrodes such as oxidation by oxygen in the air and nitridation by nitrogen in the air does not occur. Also, the side plate 13
The shield gas is guided so as to be wasteful by changing the direction of the shield gas so as to be substantially perpendicular thereto, and the entire periphery around the arc generating position can be efficiently covered on average. In this way, the gas shield is kept in a good condition, the outside air is shut off, the alteration due to oxygen and nitrogen in the air is prevented, and the generated arc is stabilized, so that a better welded part can be obtained. Obtainable. In addition, the shield cups 3 and 4 shown in FIGS.
It goes without saying that the present invention can be similarly applied to a single shield cup.

The case shown in FIG. 1 is a bottom plate 1 of a storage tank.
2 and the side plate 13 are located in a T-shaped cross section orthogonal to each other, and the longitudinal joint portion 16 between the welded portions of the side plates 13 and 13 is welded and formed by automatic TIG welding. Not limited thereto, for example, when a flat plate such as a corner portion of a rectangular box and a flat plate intersect in a T-shaped cross section or an L-shaped cross section, and one of the flat plates is abutted and welded to form a vertical direction, a horizontal direction, Alternatively, the tip of the curved tungsten electrode 20 is opposed to the welded portion at an angle close to a right angle also in the vicinity of the start end and the end of the joint to be welded along the oblique direction, etc. Welding can be performed while generating an arc to obtain a good weld. It goes without saying that the welding method is not limited to the above-described automatic method, and can be similarly applied to a TIG welding performed by a semi-automatic method or a manual method.

[0027]

As described above, according to the TIG welding apparatus of the present invention in which the tungsten electrode attached to the tip of the welding torch is formed as a curved tungsten electrode, the tip of the curved tungsten electrode has an angle close to a right angle with respect to the portion to be welded. In opposition,
An arc is generated at the shortest distance between the surface of the welded part and the electrode, and it is possible to maintain a fine and stable arc without being affected by blast, so that the surface shape of a smooth, uniform and beautiful weld bead is obtained. Good welds can be obtained. Further, since the tip of the curved tungsten electrode can be opposed to the welded portion at an angle close to a right angle as described above, a cross-sectional T-shape or a cross-sectional L-shape which has been difficult with conventional TIG welding. Butt welding in the vicinity of the intersection of the two. In addition, there is no need to rotate the TIG welding device as in the past, and it is easy and efficient to maintain a good welding condition continuously from the vicinity of the start end of the welded part with a constant inclination angle and the whole. TIG welding can be performed well.

Also, a curved tungsten electrode formed by providing a curved portion on the distal end side of the electrode and providing a linear portion at the distal end of the curved portion, when the distal end of the linear portion becomes worn and has a round shape, Since the sharpening operation is a straight portion, the operation can be easily and easily performed, and automatic polishing is also possible. The straightened portion polished and sharpened in this way can be repeatedly used while maintaining a state of being perpendicular to the surface of the portion to be welded, so that a curved tungsten electrode excellent in economy can be obtained.

Further, the TIG welding apparatus in which a cylindrical seal cover is provided at the tip of the welding torch so as to cover around the curved tungsten electrode extends and curves longer than a conventional straight tungsten electrode. Even the curved tungsten electrode is covered with a cylindrical seal cover and is always sealed with an inert gas and is shielded from the outside air, so it can be oxidized by oxygen in the air or nitrided by nitrogen in the air. No electrode deterioration occurs. In addition, since the inert shield gas can be guided and supplied in the direction opposite to the welded portion at right angles, the shield condition with the inert gas is good and oxidation such as oxidation by oxygen in the air or nitridation by nitrogen in the air is possible. There is no deterioration of the welded portion, the arc is stabilized, and a good welded portion having a more uniform surface and a beautiful appearance can be obtained.

The welding torch to which the curved tungsten electrode is attached is inclined obliquely downward with respect to the longitudinal joint of the storage tank side plate, and the tip of the curved tungsten electrode is inclined with respect to the longitudinal joint. The TIG welding device according to the present invention is formed such that they are opposed to each other at an angle close to a right angle and are automatically welded while being moved by a carriage provided along the vertical joint. An arc is generated at the shortest distance on the surface of the welded portion over the entire area from the lower end starting end to the upper part, the state of the gas shield is good, the arc is stabilized, and the automatic welding is continued in a state where the molten metal is well laminated. This makes it possible to obtain a good weld having a smooth bead shape and a beautiful appearance. In addition, automatic welding can be performed continuously and easily from the starting end of the longitudinal joint portion with good work efficiency without requiring a large-scale rotary drive device as in the related art.

[0031]

[Brief description of the drawings]

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is an explanatory side view of an embodiment of a TIG welding apparatus according to the present invention, in which a vertical joint portion near a lowermost end of a storage tank side plate is welded and partially cut away to show a section.

FIG. 2 is an explanatory diagram showing, in an enlarged manner, the vicinity of the tip of a welding torch in FIG. 1;

FIG. 3 is a partially cutaway perspective view showing a case where a vertical joint near a lowermost end of a storage tank side plate is formed by welding using a conventional TIG welding apparatus.

FIG. 4 is an explanatory side view showing a case where the vicinity of the starting end of the vertical joint at the lowermost end of the storage tank side plate is formed by welding using a conventional TIG welding apparatus, with a part thereof being cut away and a cross-section thereof;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Welding torch 2 Tungsten electrode 3 Outer shield cup 4 Inner shield cup 5 Wire 6 Nozzle tip 7 Nozzle guide 8 Torch fixing part 9 Guide fixing part 10 Wire position adjuster 11 Running rail 12 Bottom plate 13 Side plate 14 Electric motor 15 Rotating spindle 16 Vertical joint 17 Bogie 20 Curved tungsten electrode 20A Curved portion 20B Linear portion 21 Seal cover L Range from start end X Welding torch tilt angle Y Linear portion tilt angle M Curve range N Linear range

Claims (4)

[Claims] 1. A TIG welding apparatus, wherein a tungsten electrode attached to a tip of a welding torch of the TIG welding apparatus is formed as a curved tungsten electrode. 2. The TIG welding apparatus according to claim 1, wherein the curved tungsten electrode is formed by providing a curved portion on an electrode tip side and providing a straight portion at the tip of the curved portion. 3. The TIG welding apparatus according to claim 1, wherein a cylindrical seal cover formed so as to cover around the curved tungsten electrode is provided at a tip of the welding torch. 4. A welding torch to which the curved tungsten electrode is attached is inclined obliquely downward with respect to a longitudinal joint of the storage tank side plate, and a tip end of the curved tungsten electrode with respect to the longitudinal joint. The TIG welding apparatus according to claim 1, 2 or 3, wherein the TIG welding device is formed so as to face each other at an angle close to a right angle and to perform automatic welding while moving by a carriage provided along the longitudinal joint.