JP4771900B2 - Welding equipment for the production of welded steel pipes - Google Patents

Description

  The present invention relates to a welding apparatus for manufacturing a welded steel pipe that can effectively suck welding fume without adversely affecting the shielding function of shielding gas during welding of a butt portion when manufacturing a small-diameter welded steel pipe.

For example, as one method of manufacturing a square welded steel pipe, as shown in FIG. 14, two grooved steels 1 are faced to each other and the edges are butted, and the butted portion is welded by MIG welding or MAG welding. There is a so-called two-join welding method.
This two-match welding method includes an inner / outer surface welding method (FIG. 15 (A)) for welding from both sides of the outer surface and inner surface, and an outer surface welding method (FIG. 15 (B), (H) for welding the butt portion only from the outer surface. )). In addition, the outer surface welding method includes a method using a backing metal (FIG. 15B) and a back wave welding method not used (FIG. 15C). FIG. 15 is an enlarged view of part a in FIG.
In the inner and outer surface welding that welds from both sides, the groove is the X groove, but in the outer surface welding that welds from one direction, the groove is the V groove or Y groove, so the outer surface welding is more open than the inner and outer surface welding. The tip becomes large (the cross-sectional area of the groove is large), the amount of weld metal increases, and the welding cost increases. Further, when a backing material such as a backing metal is used, the welding cost is further increased.

  As described above, the inner / outer surface welding method is preferable from the viewpoint of welding costs, but when performing inner surface welding in the inner / outer surface welding method, it is necessary to insert a welding torch into the tube, so that the steel pipe to be manufactured has an outer diameter of about In the case of a 200-300 mm small-diameter tube having a long length of, for example, several meters or more, it becomes difficult to insert a welding torch into the narrow tube and perform internal welding.

  The shield gas blown out from the welding torch is a laminar flow in the vicinity of the blowout port, but becomes turbulent when it is away from the blowout port, and air is easily trapped. Therefore, when the angle of the welding torch 3 (torch angle θ) is reduced as shown in FIG. 11, the welding projection plane S has a contour as shown in the figure, and therefore turbulent flow occurs at a portion b away from the shield gas outlet. As a result, it is easy to cause a shield defect, and welding defects such as air entrainment and insufficient penetration due to the shield defect are likely to occur. Therefore, welding is generally performed at a torch angle of about 90 ° with good weldability. That is, as shown in FIG. 7 (b), the welding torch 3 is bent downward at a torch angle θ = 90 °, but considering the feedability of the welding wire 4, the radius of curvature of the welding torch R needs to be increased to some extent. For this reason, a space having a height H higher than a certain level is required.

By the way, the welding fume generated at the time of welding adheres to the welding equipment and may deteriorate the reliability of the welding equipment. Also, fume removal is an important issue in the work environment. In addition, if the shielding gas supplied to the welded portion is disturbed by fume suction and the shielding function is impaired, there is a high possibility that a welding defect such as a blow hole will occur.
For this reason, various methods have been proposed for appropriately sucking the welding fume, although it is not the case of inner surface welding of a steel pipe.
As a simple method, there is a method in which a welding hood is sucked by arranging a hood above the welded portion.
Moreover, there exists what provided the fume suction pipe in parallel with the welding torch on both sides of the welding torch along the welding line (FIG. 1 of patent document 1).
Also, there is a type using a welding torch with a suction nozzle having a double tube structure and a fume suction port on the outer tube side (FIGS. 1 and 3 of Patent Document 2).
Moreover, there exists what arrange | positions the duct which opened the several fume suction opening in the wall surface along a weld line (FIG. 4 of patent document 3).
Each of these fume suction methods has a structure in which a fume suction port is provided generally toward the weld.
Japanese Patent No. 2902571 Japanese Utility Model 6-61371 JP-A-8-103874

As described above, particularly in the case of a small-diameter pipe, it is difficult to insert a welding torch into a narrow pipe and perform internal welding, but it becomes more difficult when welding fume suction is considered.
That is, as described above, when the torch angle θ is reduced, there is a problem that a part away from the shield gas outlet is generated and the shield gas becomes turbulent and a shield failure is likely to occur. Since the wind speed in the pipe is easily affected by fume suction, there is a problem that the shield gas is easily disturbed by the airflow in the pipe.
Because of these circumstances, especially in the case of small-diameter pipes, it is necessary to be more careful than when fume suction is performed in an open space or a large-diameter pipe. It will be difficult.

Each of the conventional fume suction methods described above is difficult to apply to welding in a narrow pipe except for Patent Document 3 using a welding torch with a suction nozzle.
Although patent document 3 can be reduced in size, it cannot be said that sufficient fume suction performance can be ensured, and the welding fume that cannot be sucked in fills the pipe and adversely affects the welding equipment.
In addition, any of the conventional methods has a direct suction structure in which the fume suction port is generally directed to the welded portion, and the flow of the shielding gas is likely to be disturbed. In particular, in the case of welding in a narrow pipe, the disturbance is likely to occur significantly. Therefore, it is difficult to say that it is easy to achieve both the fume suction performance and the shielding function.

  The present invention has been made in view of the above circumstances, and does not adversely affect the shielding function of shielding gas when welding a butt portion mainly when manufacturing a small-diameter welded steel pipe by a welding method such as MIG welding or MAG welding. Another object of the present invention is to provide a welding apparatus for manufacturing a welded steel pipe capable of effectively sucking welding fumes.

The present invention that solves the above-mentioned problems provides a welding wire and a welding wire that are continuously drawn out from the opening at the tip of the welding torch in the shield gas released from the opening at the tip of the welding torch when manufacturing a welded steel pipe. The welding method of welding by generating an arc with the target base material, and sucking the welding fume generated during welding, the ends of the butted portions of the tubular material forming a tubular shape are abutted A welding apparatus for manufacturing welded steel pipes for internal welding,
A fume suction port for sucking the welding fume is provided approximately upward on the left and right sides of the welding torch so as to suck the welding fume that hits the ceiling inside the riser from the weld and descends along the left and right inner side walls. Features.

  According to a second aspect of the present invention, in the welding apparatus for manufacturing a welded steel pipe according to the first aspect, the fume suction ports are provided symmetrically on both the left and right sides of the welding torch, and the shape of the fume suction port is substantially a rectangular shape elongated in the length direction of the weld steel pipe. It is characterized by that.

  According to a third aspect of the present invention, the direction of the fume suction port in the welding apparatus for manufacturing a welded steel pipe according to the first or second aspect is an upward direction inclined toward the left and right inner side walls.

  According to a fourth aspect of the present invention, the direction of the fume suction port in the welding apparatus for manufacturing a welded steel pipe according to the first or second aspect is an upward direction inclined such that it is inclined to the left and right inner side walls and the front side is lowered. .

  According to a fifth aspect of the present invention, in the welding apparatus for manufacturing a welded steel pipe according to any one of the first to fourth aspects, the outer shape of the opening member forming the fume suction port has a fin shape that rectifies the welding fume. .

  According to a sixth aspect of the present invention, there is provided a welding apparatus for manufacturing a welded steel pipe according to any one of the first to fifth aspects, wherein the boom is inserted from the rear end side of the tubular material and moved forward and backward in the tube length direction within the tubular material. The welding torch is attached, and the torch angle of the welding torch is made smaller than 90 °.

  In the welding apparatus for producing a welded steel pipe according to the present invention, the generally upward fume suction port sucks the welding fume that hits the rising pipe inner ceiling surface from the welded portion and descends along the left and right inner side walls. Thus, since the fume suction port is generally upward, the flow of the shield gas discharged downward from the welding torch is not disturbed by the fume suction. Therefore, welding fume can be sucked appropriately without impairing the shielding function, and good welding can be obtained.

  The configuration in which the fume suction port is provided symmetrically on both right and left sides as in claim 2 and the shape of the fume suction port is a rectangular shape that is generally elongated in the weld steel pipe length direction ensures a sufficiently long opening along the side wall of the pipe inner surface. In addition, since the suction force is not concentrated in the vicinity of the welded portion, it is effective to achieve both the action of efficiently sucking the welding fumes descending along the left and right inner side walls and the disturbance of the shield gas.

  If the direction of the fume suction port is upwardly inclined toward the left and right inner side walls as in claim 3, the flow of the welding fume falling along the left and right inner side walls becomes easy to accept, so the welding fume is sucked efficiently. It becomes possible.

  If the direction of the fume suction port is an upward direction inclined so that the front side is lowered as in claim 4, the welding fume remaining in the front is sucked when adopting the retreat method in which welding is performed while retreating the welding torch. Therefore, the welding fume can be sucked efficiently.

  By making the opening member forming the fume suction port into a fin shape as in claim 5, the flow of the welding fume rising from the welded portion can be controlled to go to the fume suction port, and the fume suction performance is improved. be able to.

  If the welding torch is tilted as in claim 6, the height dimension becomes small, which is suitable for small diameter pipes. When the welding torch is tilted (when the torch angle θ is reduced), a part away from the shield gas outlet is generated, and this part is more easily disturbed by fume suction, which tends to cause a shielding failure. In the case of the inclined structure, the effect of preventing the shield gas from being disturbed as much as possible by making the fume suction port substantially upward is particularly utilized.

  Hereinafter, an embodiment of a welding apparatus for manufacturing a welded steel pipe according to the present invention will be described with reference to FIGS.

The present invention is mainly used for manufacturing a welded steel pipe, in which, when manufacturing a small-diameter welded steel pipe, inner surface welding of the butt portion of a tubular material in which end edges are butted together forms a tubular shape while sucking welding fumes generated during welding. Welding equipment.
Further, the present invention provides a welding method between a welding wire and a base material to be welded, which are continuously drawn out from the opening at the tip of the welding torch, in the shielding gas released from the opening at the tip of the welding torch. A welding method is employed in which welding is performed by generating an arc. In other words, MIG welding (Metal electrode inert gas welding) using an inert gas such as argon as a shielding gas, or MAG welding (Metal active gas welding) using carbon dioxide or a mixed gas of carbon dioxide and argon is used. To do.

In the embodiment, as shown in FIG. 14 described above, a rectangular steel pipe is manufactured by welding the butt portion of the tubular material 2 in which the two groove steels 1 face each other and the edges are abutted to form a tubular shape. It is. In addition, the thing in the state before welding which just made two channel steels 1 face each other and butted the end edges, or the state which has not finished the welding of full length is called a tubular material (However, for convenience of explanation, such a case is sometimes called a steel pipe.)
The embodiment described below employs the inner / outer surface welding method described with reference to FIG. 15 (a) when manufacturing a welded steel pipe, and is applied to inner surface welding work in the inner / outer surface welding. In the following explanation, two grooved steels 1 which are formed in a tubular shape by facing each other in the opposite direction are constrained by some means and inner surface welding of the butt portion on the lower surface side is performed, or one butt portion In this case, the inner surface of the other butt portion is welded after the above welding is completed.

  FIG. 1 is a side view illustrating an overall configuration of a welding apparatus (hereinafter, simply referred to as a welding apparatus in some cases) 10 for producing a welded steel pipe of an embodiment, where (a) is a welding work preparation state, and (b) is a welding work. The state at the start, (c) indicates the state in which the welding operation is in progress.

2 is an enlarged view of the main part of FIG. 1 (a), FIG. 3 is an enlarged view of the main part of FIG. 1 (c), FIG. 4 is a plan view of FIG. 3, and FIG. It is.
In these drawings, 13 is a welding torch for MAG welding, for example. The welding torch 13 has a structure in which the welding wire 4 is inserted through the center portion and a shield gas is blown out from the tip. The welding torch 13 is attached to a front end portion of a long boom 18 that can be taken in and out of the tubular material 2 by a boom drive device 17, and extends along the boom 18 to a device main body portion 21 at the rear end portion. It is connected to the. The welding torch tube 20 serves as a passage for sending the welding wire 4 and the shielding gas to the welding torch 13. The apparatus main body 21 includes a welding power source, a wire supply device that supplies a welding wire 4 wound in a coil shape, a gas cylinder that supplies a shielding gas, a fume discharge unit, and the like.

A boom head 22 is connected to the tip of the boom 18, and the welding torch 13 is directly attached to the boom head 22.
The boom head 22 is connected to the tip of the boom 18 via a movable mechanism 23. The movable mechanism 23 allows the boom head 22 to swing in the left-right direction as viewed from above, and allows the boom head 22 to move vertically up and down with respect to the boom 18. And a horizontal movable part 26 that allows the boom head 22 to move horizontally to the left and right with respect to the boom 18.
At two positions in the front and rear of the center of the lower surface of the boom head 22, there are provided copying wheels 28 that fit into the groove (V groove) 2 a of the butting portion and roll. When the boom head 22 is moved, the copying wheel 28 is fitted into the groove to position the boom head 22, and the front end of the welding torch 13 attached to the boom head 22 is properly aligned with the groove 2a. do.
Although the detailed structure of the movable mechanism 23 is omitted, when the boom head 22 moves backward, it does not restrain movement other than movement of the boom head 22 in the tube length direction, that is, the copying wheel 28 rolls along the groove. Anything that allows movement following the movement is acceptable. For example, a structure in which the horizontal angle movable unit 24 is connected via a vertical rotation shaft, a vertical movable unit 25 is a horizontal slide structure in combination with vertical ants and ant mizo, and a horizontal ant and ant mizo is used as the horizontal movable unit 26. A vertical slide structure or the like can be adopted in combination with, and various other structures are possible.
In addition, the boom 18 includes a boom support wheel 29 that supports the boom 18 by rolling an inner bottom portion of the tubular material 2 and an external table 30 continuous thereto.

  In this invention, the opening member 31 provided with the fume suction port 31a which attracts | sucks the welding fume which generate | occur | produces at the time of welding is attached to the front-end part of the boom head 22, and the fume discharge tube 32 connected to this opening member 31 is a boom head. 22 and the boom 18 are inserted to the apparatus main body 21 side. Details will be described later.

  In this embodiment, the welding torch 13 is welded by a retreating method in which welding is performed while retreating along the groove 2a. That is, as shown in FIGS. 1 to 4, etc., the boom 18 that supports the welding torch 13 is not positioned above the welding bead 5, and the welding torch 13 is moved while moving away from the welding bead 5. To do.

If the forward method as shown in FIG. 6 (b) is adopted, the welding equipment receives the radiant heat of the welding bead, so that the protection structure from the radiant heat needs to be strict, and the welding equipment becomes large.
However, by adopting the retreat method shown in FIG. 6 (a), the welding equipment (the welding torch 13 and each portion arranged along the boom 18) is less likely to receive the radiant heat of the welding bead. Therefore, the protection structure from radiant heat can be simplified, and the welding equipment can be downsized.
Further, as described above, as the copying apparatus for the groove position, a simple structure in which the copying wheel 28 is simply fitted into the groove can be employed, so that the copying apparatus can be simplified.

In the embodiment, the torch angle θ of the welding torch 13 is set to 50 to 70 ° instead of a right angle as shown in FIG. Further, the welding torch 13 of the embodiment is a water-cooled torch having a radius of curvature R of about 70 mm, for example, and cooling the torch by feeding cooling water. Although a cooling water pipe is connected to the welding torch 13, the illustration is omitted.
Note that the range of the torch angle of 50 to 70 ° is obtained as a result of various experiential searches for conditions that allow good welding by changing the torch angle θ in various ways, although details are omitted.

The opening member 31 forming the fume suction port 31a will be described in detail. As shown in FIGS. 3 to 5 and the like, the opening member 31 is provided symmetrically on both sides of the welding torch 13, and In both cases, the fume suction port 31a is generally upward.
The fume suction port 31a of the embodiment is substantially a quadrangle that is elongated in the length direction of the tubular material 2, and is inclined so that the upper end is closer to the inner surfaces of the left and right side walls.
Further, the outer shape of the opening member 31 that forms the fume suction port 31a has a fin shape that rectifies the welding fume. Here, the fin shape indicates that the outer shape of the opening member 31 is flat (therefore, the width of the internal space is substantially the same as the width of the fume suction port 31a). However, it is not necessarily flat, and in some cases, a curved surface may be considered for controlling the flow of the welding fume. The portion 31b of the opening member 31 connected to the fume discharge tube 32 is arbitrary, such as a rectangular cylinder, a cylinder, an elliptic cylinder, or a long cylinder.

When the inner surface of the tubular member 2 is welded by the welding device 10, the boom driving device 17 is driven to advance the boom 18, and the welding torch 13 is moved to the front end of the tubular member 2 as shown in FIG. Move. The means for driving the boom 18 is arbitrary, and the apparatus main body 21 at the rear end of the boom 18 may be installed on the carriage to drive the carriage.
In FIG. 1, reference numeral 35 denotes an auxiliary plate for good welding at the welding start position.
While the welding torch 13 is retracted from the position shown in FIG. 1B together with the boom 18 as shown by the arrow, the welding wire 4 is fed out from the tip to the groove and the shielding gas is released to perform welding in the shielding gas.

A welding experiment in which the inner surface of the butt portion of the tubular material 2 is welded by the welding apparatus 10 will be described.
The steel pipe to be manufactured is a square steel pipe of 19 mm (plate thickness) × 200 mm (side length) × 200 mm (side length). The grooved steel 1 used is a press-formed steel plate. The welding method is MAG welding using carbon dioxide gas as a shielding gas. The groove conditions are a Y groove and a groove depth of 6 mm. The welding wire had a diameter of 1.2 mm, and experiments were conducted using both solid wires and flux-cored wires.
FIG. 9 shows the results of a welding experiment in which the torch angle θ is varied in the range of 45 to 90 ° with respect to the welding speed of 40 to 80 cm / min. 9A shows a case where a solid wire φ1.2 mm is used as the welding wire 4, and FIG. 9B shows a case where a flux-cored wire φ1.2 mm is used.
As shown in the figure, in the range of welding speeds of 50 to 60 cm / min., Good welding was obtained with a torch angle of about 50 ° or more for a solid wire and about 60 ° or more for a flux-cored wire. In the case of the flux-cored wire, good welding was obtained even at a welding speed of 70 cm / min. From this experimental result, it is possible to obtain good welding if the torch angle θ is up to 50 °, but a range of 60 ± 10 ° is preferable, for example.
The welding speed at which good welding is possible is also related to the diameter of the welding wire, and the relationship between the two may be selected appropriately.

Since the present invention is welding in a pipe, when fume suction is not performed, the welding fume rises from the welded portion (the weld bead 5 portion) and descends along the inner surfaces of the left and right side walls as shown in FIG. It becomes.
Here, as shown in FIG. 12B, when welding fume (shown by a solid line) is sucked by a direct suction method in which the fume suction port is directed directly to the welded portion, such as by providing a hood 6 above the welded portion. If the suction air speed is increased in order to obtain a sufficient fume suction effect, the shield gas (shown by a broken line) is also easily sucked, and the shield function of the shield gas is impaired.
However, in the welding apparatus of the present invention, as shown in FIGS. 8 (a), (b), and (c), the welding fume rising from the welded portion hits the ceiling surface in the pipe and descends along the left and right inner sidewalls. When coming, the shield gas appropriately sucked from the fume suction port 31a and released downward from the welding torch 13 is not directly affected by the suction by the upward fume suction port 31a, and the flow of the shield gas Will not be disturbed.
If the shielding gas that blocks the atmosphere and protects the welded part becomes turbulent at the welding position, the atmosphere may be trapped and welding defects such as blowholes may occur. It is necessary to set the flow range to 2 m / s or less, and it is desirable that the wind speed in the vicinity of the welded portion is 1 m / s or less in order to perform sound welding. If the welding fume as described above is sucked from the upward-facing fume suction port 31a, the wind speed at the shield gas welding portion can be reduced to 1 m / s or less while ensuring sufficient suction of the welding fume. Thus, both the welding fume suction performance and the shielding function can be ensured.

FIG. 10 shows the test results of the nitrogen amount analysis test performed to confirm the shield function. Since the amount of nitrogen increases when the shield gas is blown by the wind, it is possible to measure whether the shield gas covers the welded part by measuring the amount of nitrogen in the gas near the welded part, that is, the shielding function. it can.
Under the conditions of this welding experiment, the relationship between the wind speed and the amount of nitrogen was as shown by the curve in FIG. Blow holes frequently occurred at a wind speed of 1.5 m / s, but good welding was obtained at a wind speed of 1.0 m / s.
As described above, this wind speed is a wind speed capable of maintaining a laminar flow state without the shield gas becoming turbulent.
In the case of welding in a pipe, air flows into the pipe from the outside by performing fume suction, but if the suction air volume is increased for sufficient fume suction, the amount of air flowing into the pipe and the cross-sectional area of the pipe Therefore, in the case of a small-diameter pipe, the inflow speed into the pipe becomes large. However, it is possible to reduce the wind speed at the welded portion to 1 m / s or less by fume suction from the upward fume suction port 31a.

FIG. 13 shows another embodiment of an opening member for forming a fume suction port. In this opening member 41, similarly to the above embodiment, rectangular fume suction ports 41a elongated in the weld steel pipe length direction are provided symmetrically on both the left and right sides, and the direction of the fume suction ports 41a is on the left and right inner side walls. Although it is inclined upward, the fume suction port 41a of the opening member 41 is further inclined so that the front side is lowered. The portion 41b of the opening member 41 connected to the fume discharge tube 32 is arbitrary, such as a rectangular cylinder, a cylinder, an elliptic cylinder, or a long cylinder.
As described above, when the direction of the fume suction port 41a is an upward direction inclined so that the front side is lowered, in order to suck the welding fume remaining in the front in the case of adopting the retreat method in which welding is performed while retreating the welding torch. Appropriate and efficient suction of welding fume.
The opening member 41 has a flat outer shape and a fin shape that rectifies the welding fume, as in the previous embodiment.
The shape of the opening member 41 in the illustrated example is narrower toward the portion 41b connected to the fume discharge tube 32 (see FIG. 13A). In this case, it is good also as a cross-sectional shape where the lower part of the opening member 41 becomes wider than upper part (part of the fume suction port 41a).

In the above-described embodiment, as the steel material for manufacturing the square welded steel pipe, the grooved steel by press forming is used, but it is naturally possible to use the hot rolled grooved steel.
Further, the present invention can be applied to a case where a round steel pipe is manufactured instead of a square steel pipe. In this case, one steel plate is curved and formed into a circular cross section, and the butted portion of the edge is internally welded by the welding apparatus for manufacturing a welded steel pipe of the present invention.

  The welding method is not limited to MAG welding using a mixed gas of carbon dioxide and argon as the shielding gas, but MIG welding using an inert gas such as argon may be employed. In short, in the shield gas released from the opening at the tip of the welding torch, welding is performed by generating an arc between the welding wire that is continuously drawn out from the opening at the tip of the welding torch and the base material to be welded. Any welding method may be used as long as the welding method is performed and welding is performed while suctioning the welding fume generated during welding.

BRIEF DESCRIPTION OF THE DRAWINGS It is a side view which shows the outline of the whole structure of the welding apparatus for welded steel pipe manufacture which applies this invention, (A) is a welding operation preparation state, (B) is the state at the time of a welding operation start, (C) is a welding operation. Indicates the ongoing state. 1 shows an embodiment of a welding apparatus for manufacturing a welded steel pipe according to the present invention, and is a detailed enlarged view of a main part of FIG. It is a detailed principal part enlarged view of FIG. FIG. 4 is a plan view of FIG. 3. It is an AA arrow line view of FIG. The moving direction of the welding torch will be described. (A) is an explanatory view of the retreat method employed in the embodiment, and (b) is the advance method. The angle of the welding torch (torch angle θ) will be described. (A) shows the case of the torch angle θ employed in the embodiment, and (B) shows the case of a general torch angle of 90 °. It is a figure explaining the flow of the welding fume and shield gas at the time of performing inner surface welding of a tubular material with the welding apparatus for welded steel pipe manufacture of the present invention, (I) in FIG. 3, (B) in FIG. (C) is a diagram corresponding to FIG. 5 respectively. The result of the welding experiment which searches the torch angle (theta) in which favorable welding is possible is shown, (A) is the case of a solid wire and (B) is the case of a flux-cored wire. It is a figure which shows the test result of the nitrogen content analysis test performed in order to confirm the shield function in the welding apparatus provided with the fume suction port of this invention. It is a figure for demonstrating the problem when a welding torch is inclined (when a welding torch has torch angle (theta)). It is a figure for demonstrating the flow of the welding fume and shield gas at the time of performing internal welding of a square steel pipe, (b) is not performing fume suction, (b) is directly sucked by a suction hood placed above If you do. The other Example of the opening member which forms a fume suction opening is shown, (A) is a side view, (B) is a front view. It is a figure explaining the square-shaped welded steel pipe which manufactures two channel steels facing each other and welding the butt | matching part of end edges. FIG. 15 is a diagram for explaining a welding method for a butt portion in FIG. 14, where (a) shows an inner and outer surface welding method, and (b) and (c) show an outer surface welding method.

Explanation of symbols

1 Channel steel 2 Tubular material (steel pipe before welding)
2a Groove 4 Welding wire 5 Welding bead 10 Welding device for producing welded steel pipe (welding device)
DESCRIPTION OF SYMBOLS 13 Welding torch 17 Boom drive device 18 Boom 20 Welding torch tube 21 Device main-body part 22 Boom head 23 Movable mechanism 24 Horizontal angle movable part 25 Vertical movable part 26 Horizontal movable part 28 Copy wheel 29 Support wheel 30 External tables 31, 41 Opening member 31a, 41a Fume suction port 32 Fume discharge tube

Claims (6)

When producing a welded steel pipe, an arc is formed between the welding wire and the base material to be welded that are continuously drawn out from the opening at the tip of the welding torch in the shield gas released from the opening at the tip of the welding torch. For welding welded steel pipes that weld the inner surface of the abutting portion of the tubular material in which the end edges are abutted to each other while sucking the welding fume generated at the time of welding. A welding device,
A fume suction port for sucking the welding fume is provided approximately upward on the left and right sides of the welding torch so as to suck the welding fume that hits the ceiling inside the riser from the weld and descends along the left and right inner side walls. A welding apparatus for manufacturing welded steel pipes.   The welding for manufacturing a welded steel pipe according to claim 1, wherein the fume suction port is provided symmetrically on both the left and right sides of the welding torch, and the shape of the fume suction port is a rectangular shape that is generally elongated in the weld steel pipe length direction. apparatus.   The welding apparatus for manufacturing a welded steel pipe according to claim 1 or 2, wherein the direction of the fume suction port is an upward direction inclined toward the left and right inner side walls.   The welding apparatus for manufacturing a welded steel pipe according to claim 1 or 2, wherein the direction of the fume suction port is an upward direction that is inclined so as to incline toward the left and right inner side walls and lower on the front side.   5. The welding apparatus for manufacturing a welded steel pipe according to claim 1, wherein the outer shape of the opening member forming the fume suction port is a fin shape that rectifies the welding fume.   The welding torch is attached to the front end portion of the boom inserted from the rear end side of the tubular material and made movable in the tubular length direction in the tubular material, and the torch angle of the welding torch is made smaller than 90 °. A welding apparatus for producing a welded steel pipe according to claim 1.

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