JPH11104827A - Nozzle stub mag welding method and welding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize automatic MAG welding and to enable high efficiency/high quality mounting by welding when a nozzle stub is subjected to mounting by welding to a member to be mounted. SOLUTION: A parallel narrow groove 3 is formed around a nozzle stub 2, after discharge of a shield gas is started from an auxiliary shield ring 9 toward the groove 3, while rotation of a welding torch 7 and a curved tip 8 make a wire tip depict a circular arc and oscillate, the inside of a groove 3 is welded by turning/travelling the welding torch 7, the welding torch is turned by one round around the stub 2 and then reversed, by repeating this, a weld metal is laminated, mounting of the stub 2 to a member 1 to be mounted is made.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nozzle MAG (MA) applied to the mounting of a nozzle nozzle of a drum for various large structures.
G: Metal Active Gas) welding method and welding machine.

[0002]

2. Description of the Related Art As shown in FIG. 13, 150 to 200 nozzles 2 of large and small sizes are attached to a boiler drum by welding at a narrow pitch in a longitudinal direction and a circumferential direction of the boiler drum 1. .

In the conventional mounting of the nozzle 2 of the boiler drum 1, a groove to be welded is an ordinary wide groove 3a as shown in FIG. 14, and a plurality of passes in the width direction of the groove 3a are welded. Therefore, continuous welding cannot be performed because the inclination angle of the welding torch must be adjusted for each pass. Further, the pitch of the nozzle 2 was so small that the welding torch could not be automated due to contact with an adjacent pipe.

[0004] For this reason, in mounting the nozzle 2 of the conventional boiler drum 1 shown in FIG. 14, it has been carried out by semi-automatic MAG welding that requires manual work of a highly skilled worker.

[0005]

In the conventional installation of the nozzle of the boiler drum, the inclination angle of the welding torch must be adjusted for each pass in the groove width direction for welding as described above. Semi-automatic MAG welding has been employed because continuous welding cannot be performed and automation cannot be performed due to the welding torch contacting an adjacent pipe.

[0006] However, this semi-automatic MAG welding is
An operator having a high level of skill is required, and there is a limit to improvement in welding quality and work efficiency, and realization of automatic MAG welding has been desired. The present invention seeks to solve the above problems.

[0007]

[Means for Solving the Problems]

(1) In the nozzle MAG welding method of the present invention, a parallel narrow groove is formed which goes around the nozzle installed on the member to be mounted and is inclined toward the center of the nozzle, and is attached around the nozzle. An auxiliary shield ring is arranged on the member surface, a welding machine is arranged on the nozzle, and the tip of a welding torch provided with a curve tip at the tip is inserted into the groove, and turned toward the groove. After starting the discharge of the shielding gas from the auxiliary shield ring, adjust the oscillating width and the stop time at both ends to rotate the welding torch and oscillate the tip of the welding wire with the curve tip, while moving around the nozzle. The turning traveling of the turning welding torch is started to perform welding within the groove, and when the welding torch has made one revolution, the oscillate is stopped, the welding current is reduced and the welding torch is inverted, and the oscillate after the welding torch is inverted. By restarting and returning the reduced welding current, the welding torch is turned in the opposite direction, and the welding torch is repeatedly turned and inverted, thereby repeatedly laminating the weld metal in the groove and connecting the pipe to the attached member. It is characterized in that the table is attached.

In the present invention, since the welding torch that rotates around the center of the nozzle stub is inclined at an angle that does not make contact with the adjacent pipe and forms a parallel narrow groove that makes a round around the nozzle, the inside of the groove is formed. It becomes possible to laminate the weld metal from the bottom to the surface under constant welding conditions.

Further, when the welding torch turns and runs from the welding start point to perform welding and returns to the start point again,
The welding can be reversed without interrupting the turning, and the welding can be performed by turning in the opposite direction to perform the welding. Since the turning and the turning can be repeated, continuous welding can be performed.

Further, the groove to be welded is sealed by the shielding gas discharged from the auxiliary shield ring, and the tip of the welding wire is rotated by the rotation of the welding torch and the curved tip provided at the tip of the welding torch. Oscillation is performed by drawing an arc in the direction of the welding torch's direction of travel, and the width of this oscillate and the stop time at both ends can be controlled, so that it is possible to achieve good welding with sufficient penetration and stable quality. Become.

(2) A nozzle MAG welding machine according to the present invention is a clamp jig which is inserted into a nozzle and fixed to the nozzle, a turning mechanism which is fitted and fixed to the clamp jig, and an upper part of the turning mechanism. , A horizontal slide attached to the side of the turning mechanism, a wire protrusion length control slide provided at one end of the horizontal slide, and a welding provided on the wire protrusion length control slide A torch and a wire feeding mechanism mounted on the other end of the horizontal slide are provided.

In the present invention, since a clamp jig which is fixed to the nozzle and is capable of fixing the turning mechanism is provided, after fixing the clamp jig to the nozzle, the turning mechanism is fixed thereto. It is possible to easily attach the welding machine to the nozzle.

[0013] A horizontal slide is attached to the turning mechanism, and a welding torch is provided at one end of the horizontal slide via a wire projection length control slide. By adjusting the control slide, the welding torch can be set by inserting the tip of the welding torch into a groove provided around the nozzle while tilting the welding torch so as not to contact the adjacent nozzle.

Further, since a wire feeding mechanism for automatically feeding a wire to the welding torch is provided at the other end of the horizontal slide, the turning mechanism turns the horizontal slide, and the turning mechanism turns every horizontal rotation. By repeating the reversal, it is possible to perform the lamination continuous welding in the groove by the welding torch.

Further, the current to the welding torch, cooling water,
Since the supply of the shielding gas is performed via a slip ring mechanism provided above the turning mechanism, good energization, cooling of the welding torch, and sealing of the welded portion are possible, and in particular, water leakage is prevented. There is none, and good welding is possible.

(3) The present invention provides the nozzle MAG welding machine according to the invention (2), wherein the turning mechanism has a hollow shaft having a spur gear and coupled to the clamp jig. A base plate connected to the horizontal slide and connected to the horizontal slide, a turning drive mechanism provided on the base plate and connected to the spur gear, and a turning position detection sensor provided on the base plate; The mechanism is characterized in that the mechanism is provided with a current supply section, a cooling water flow section, and a shield gas ventilation section.

According to the present invention, the turning torch for welding the inside of the groove is provided by the turning mechanism including the hollow shaft, the base plate which turns and turns around the hollow shaft by the turning drive mechanism, and the turning position detecting sensor of the base plate. Satisfactorily turning and reversing is possible. In addition, the slip ring mechanism has a current-carrying part, a water-permeable part, and a ventilation part,
Good energization of the welding torch, cooling of the welding torch, and sealing of the welded portion are possible.

(4) According to the present invention, in the nozzle MAG welding machine according to the invention (2), the wire projection length control slide includes a rotary plate that can change an angle of attachment to the horizontal slide. It is characterized by.

In the present invention, since the attachment of the wire protrusion length control to the horizontal slide is performed through the rotary plate having a variable attachment angle, adjustment for adjusting the inclination of the welding torch to the inclination angle of the groove is performed. It will be easier.

(5) The present invention provides the nozzle MAG welding machine according to the invention (2), wherein the welding torch penetrates the torch main body connected to the wire protrusion length control slide and the torch main body. An outer cylinder, a curve tip provided at the tip of the outer cylinder, an inner cylinder through which the welding wire provided in the outer cylinder and supplied to the curve tip passes, and an inner cylinder provided on the torch body. A rotation drive mechanism for repeatedly rotating the outer cylinder is provided.

In the present invention, the tip of the curve tip draws an arc in the traveling direction by repeatedly rotating the outer cylinder by the rotary drive mechanism, and the tip of the welding wire performs an arc-shaped oscillating operation. The wall of the succeeding flat is sufficiently melted, and good welding can be performed.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a description will be given of a welding apparatus applied to a boiler drum nozzle MAG welding method according to an embodiment of the present invention.

A welding apparatus applied to the welding method according to the present embodiment shown in FIG. 1 includes a clamp jig 4 which is fitted in a nozzle 2 provided on a boiler drum 1, and a jig provided and provided on the jig 4. A horizontal slide 5 that rotates horizontally about 4;
A welding machine provided with a wire protrusion length control slide 6 disposed on the horizontal slide 5 and a welding torch 7 into which the tip 8 disposed on the control slide 6 and provided at the tip is inserted into the groove 3; The nozzle 2 is formed by an auxiliary shield ring 9 having the same central axis as the central axis and disposed on the surface of the boiler drum 1 and discharging a shield gas.

Next, a nozzle MAG welding method according to the present embodiment, which is performed using the above-described welding apparatus, will be described with reference to FIGS. In the welding method according to the present embodiment shown in FIGS. 1 to 5, the welding torch 7 whose tip is inserted in advance and turns around the center of the nozzle 2 around the center of the nozzle 2 does not contact the adjacent pipe. As shown in FIG. 2, a parallel narrow opening 3 which is inclined and makes a round around the nozzle 2 is formed.

Next, after the auxiliary shield ring 9 is disposed on the surface of the boiler drum 1 with the central axis of the nozzle 2 as its center, the clamp jig 4 is fitted into the nozzle 2 and a welding machine is attached to the welding torch. 7 is inserted into the groove 3.

In this state, as shown in FIG. 3, after the discharge of the shield gas 18 from the auxiliary shield ring 9 toward the center of the nozzle 2 and the groove 3 is started, the welding torch 7 is started.
, And while oscillating with the tip 8 as shown in FIG. 4, the welding torch 7 is turned by the horizontal slide 5 to make one round around the nozzle 2, and the groove 3 is formed.
5 from the start point 16 shown in FIG. 5 to the reversal position (the same position as the start point 16).

When the welding torch 7 reaches the reversing position 17, the oscillating by the tip 8 is stopped, the welding current is reduced, and the welding torch 7 is reversed at high speed as shown in FIG. After the reversal of the welding torch 7, the height of the welding torch 7 is adjusted by the wire protrusion length control slide 6 to a height corresponding to the bulge of the welding metal 13, the reduced welding current is restored, and the oscillate is resumed. Welding is performed by making the welding torch 7 make a full turn in the opposite direction.

The turning and reversing of the welding torch 7 are continuously repeated, and the welding metal 13 is stacked in the groove 3. When the height of the stacked welding metal 13 reaches a predetermined height. Then, the welding for attaching the nozzle 2 to the boiler drum 1 is completed.

The details of the oscillating by the tip 8 at the time of welding by the welding torch 7 will be described below with reference to FIG. This tip 8 is attached to the tip of the welding torch 7, and the tip of the tip 8 is in the traveling direction 1 of the welding torch 7.
5, the tip of the welding torch 7 turns left and right by the rotation of the welding torch 7 to draw an arc, and the welding wire 10 sent from the welding torch 7 is sent out from the tip.

Therefore, the tip of the welding wire 10 sent out from the tip 8 oscillates while drawing an arc toward the traveling direction 15 of the welding torch 7 having a predetermined oscillating width 12, and generates an arc 14 from the tip. .

The rotation angle 11 of the welding torch 7 for determining the oscillating width 12 of the welding wire 10 and the time for stopping the rotation of the welding torch 7 at both ends of the arc drawn by the tip of the welding wire 10 are appropriately controlled. I can do it.

In the present embodiment, since the welding torch swiveling around the center of the nozzle stub is inclined at an angle that does not make contact with the adjacent pipe, and forms a parallel narrow groove that makes a round around the nozzle stub. It has become possible to laminate metal under constant welding conditions from the lowermost part of the tip to the surface.

Further, the tip of the wire is bent by the curved tip in the traveling direction of the welding torch, and oscillates by the tip of the wire which turns right and left by the rotation of the welding torch and draws an arc. Since the stop time can be controlled appropriately, sufficient penetration of the weld metal and stable quality can be ensured, and good welding can be performed.

Further, the welding is performed by turning the welding torch from the start point of welding to perform welding, and when returning to the start point again, the welding torch is reversed without interruption, and the welding is performed by turning in the opposite direction to perform welding. Because of the repetition, continuous welding in which the weld metal is continuously stacked in the groove has become possible.

Further, an auxiliary shield ring is provided on the surface of the boiler drum on the outer periphery of the nozzle, and the shield gas is discharged from the ring toward the center and the groove of the nozzle to mix air from the outer surface and the upper surface. In order to keep the shield inside the groove well and to prevent welding, good welding became possible.

Next, a welding machine applied to carry out the nozzle MAG welding method according to this embodiment will be described with reference to FIGS.
This will be described specifically and in detail below. This welding machine is attached to a nozzle 2 provided on a boiler drum 1 shown in FIG.

The overall structure of the welding machine is shown in FIG.
7A and 7B show the operation of attaching to the nozzle 2, but when attaching to the nozzle 2, first, as shown in FIG. Then, the welding machine is mounted on the nozzle 2 by fixing the turning mechanism 104 to the clamp jig 4 as shown in FIG. 7B.

Above the turning mechanism 104, a slip ring mechanism 105 is provided, through which electric power is supplied to an electric system and cooling water and a shield gas are supplied. At one end of the horizontal slide 5 attached to the side surface of the turning mechanism 104, a wire protrusion length control slide 6 is provided, and the tip of the welding torch 7 attached to this is inserted into the groove.

At the other end of the horizontal slide 5, a wire feed motor 109, a wire reel 110, and the like are mounted. As shown in FIG.
From 0, the welding wire is fed to the welding torch 7 via the conduit cable 111, and after arc start, the welding torch 7 turns while performing oscillating to perform continuous welding.

The details of the clamp jig 4 will be described with reference to FIG. The clamp jig 4 is fixed to the nozzle 2 by fitting the clamp body 112 into the nozzle 2 and then turning the handle 113 to raise the tapered block 115 via the shaft 114, and the clamp piece 11
6 is performed.

The removal is performed after the handle 113 is turned in the opposite direction and the clamp piece 16 is housed by the tension coil spring 117 provided around the clamp piece 116. Reference numeral 118 denotes a guide plate, and 119 denotes a knob.

The details of the turning mechanism 104 will be described with reference to FIG. The welding machine can be held by inserting the hollow shaft 20 of the turning mechanism 104 into the clamp jig 4 fitted in the nozzle 2 and fixing it with the clamp lever 21. A spur gear 22 is fixedly fastened to the hollow shaft 20 by a bearing nut 23.
, A housing 25 and a base plate 26 are attached.

A gear case 27 is provided on the base plate 26.
The spur gear 32 is rotated via bevel gears 29 and 30 and a shaft 31 by driving the turning motor 28. The spur gear 32 is screwed with the spur gear 22,
Since the spur gear 22 is fixed, when the spur gear 32 rotates, the spur gear 32 turns around the spur gear 22 and the base plate 26 turns.

The proximity switch 33 provided on the base plate 26 is for detecting the origin when turning, and detects the origin by detecting the dog 34 attached to the spur gear 22. The proximity switch 35 is for detecting the turning position, and detects the turning position by detecting the number of teeth of the spur gear 22, and is important in setting welding conditions and performing welding. 36 is a gear cover.

The base plate 26 has an L-shaped support 3
7, a frame formed by the plate 38 and the bracket 39 is provided, and the horizontal slide 5 is incorporated and fixed in the frame.

Regarding the slip ring mechanism 105,
The details will be described with reference to FIG. The slip ring mechanism 105 is mounted and fixed on the upper surface of the hollow shaft 20 of the turning mechanism 104, and has a structure capable of supplying electricity to the electric system and supplying cooling water and shield gas.

The power cable 40 from the welding power source passes through the hollow shaft 57 from above and is fixed to the power supply bolt 41. The welding current is supplied to the power supply ring 42, the brush 43, the power supply ring 44, the power supply shoe 45, and the power supply bolt 46. Through the power supply block 46 ', from which the power is further supplied to the welding torch.

Six energizing shoes 45 are provided at equal intervals around the energizing ring 44, and are uniformly pressed by the spring 48 in the spring holder 47 to the energizing ring 42, so that good energization can be performed. .

The pivot mechanism 1 is attached to the pivot mechanism 104.
This is performed by mounting an insulating flange 50 incorporating an O-ring 49 on the upper surface of the hollow shaft 20 of the housing 04. A hollow rotor 51 is mounted thereon, and a housing 53 and an insulating ring 54 are mounted via a bearing 52. And has an insulating structure with the fixed-side hollow rotor 51.

A hollow shaft 57 is mounted and fixed on the upper surface of the hollow rotor 51 via an insulating flange 56, and a slip ring 58 for energizing the electric system is fitted outside the hollow shaft 57, and is fixed by a ring 59. Reference numeral 60 denotes a slip ring cover, and 61 denotes a non-rotating guide shaft, which is fixed to the insulating flange 55.

Further, a turning mechanism 104 is formed by a guide shaft 62 and a bracket 63 attached to the side surface of the insulating flange 55.
And the rotating side including the insulating flange 55 rotates together with the base plate 26 of the turning mechanism 104. The current-carrying part described above is attached to the insulating flange 55.

The fixed-side hollow rotor 51 is provided with a hole and a groove for supplying the shielding gas for communicating the shielding gas supply pipes 106 and 107, and the O-ring 5 is divided into five stages.
4 mounted, each housing being a rotating side
3 is sealed.

As shown in FIG. 10B, a cooling water supply pipe 101 and a cooling water drain pipe / power supply cable 1 each having one end connected to the welding torch 7 are provided in the power supply block 46 '.
02 is connected to a cooling water supply device (not shown) to circulate cooling water. The feature of this cooling water system is that a seal with almost no water leakage is provided.

The details of the wire protrusion length control slide 6 will be described with reference to FIG. The wire protrusion length control slide 6 is attached to the horizontal slide 5 fixed to the turning mechanism 104 with a circular rotary plate 65, and has a structure in which the inclination angle can be adjusted according to the nozzle groove angle.

A base plate 66 is fixed to the rotary plate 65. A screw shaft 68 is rotated by a vertical drive motor 67 attached to an end of the base plate 66, and a slider 69 moves up and down. 70
Is a linear motion (LM) guide for smoothly moving the slider 69 up and down.

The docks 71 and 72 are provided on the side of the slider 69.
Are mounted, and the detection of the upper and lower ends is performed by the proximity switch 73a,
This is performed at 73b. The proximity switch 74 is used for initial setting of the torch position. When the apparatus is set, the tip of the welding torch 7 attached to the bracket 75 of the slider 69 can be guided into the groove and positioned.

The welding torch 7 will be described in detail with reference to FIG. The torch body 76 is attached to the wire protrusion length control slide 6 with the bracket 75 described above. The torch main body 76 has a torch inner cylinder 79 and a torch outer cylinder 80 in which an inner tube 78 insulated by an insulating bush 77 is incorporated.

The above-described conduit cable 111 is connected to the upper joint 81, and the welding wire 10 having passed through the rotary shaft 82 passes through the inside of the torch inner tube 79, and is fixed to the torch outer tube 80 with the lock nut 83.
4 is sent. 85 is a locking key.

At the lower part of the torch body 76, two shield nozzles 86a and 86b are inserted in front and rear of the torch outer cylinder 80, and are fixed by a nozzle holder 87. By supplying the shielding gas through the torch body 76 to the vicinity of the curve tip 84, the shielding effect at the time of welding is further enhanced.

Cooling water is supplied from the cooling water supply pipe 101 to a gap between the torch inner cylinder 79 and the inner tube 78 shown in FIG. 12 (c), and falls down this gap to reach the lower end. From above, the gap between the inner tube 78 and the torch outer cylinder 80 is raised and drained to the cooling water drain pipe / feeding cable 102, so that the welding torch 7 is effectively cooled.

A casing 88 is provided above the torch body 76.
A rotation motor 90 is provided on a motor base 89 attached to the motor. When the rotation motor 90 is driven, the rotation of the rotation motor 90 is fixed to a torch outer cylinder 80 via a timing pulley 91 and a timing belt 92.
To rotate and oscillate the welding torch 7.

The rotation angle is detected by a potentiometer 96 mounted via a joint shaft 94 and a coupling 95 directly connected to the rotation motor 90. 97 is a potentiometer case, 98 is a cover.

When the welding of the nozzle 2 to the boiler drum 1 is performed by using the present welding machine, the turning mechanism 104 of the welding machine is fixed to a clamp jig 4 fitted and mounted on the nozzle 2, The welding torch 7 tilted at an angle that does not contact the adjacent nozzle stub 2 can be inserted into the groove and set by making the center of 2 a turning center and making it parallel to the groove angle of the nozzle 2.

Further, the swivel mechanism 104 can be turned around the center of the nozzle stub 2 as a swivel center, and a slip ring mechanism 105 is used to supply electric power from an externally installed welding power source, a control panel, etc. Shield gas can be supplied.

In this slip ring mechanism 105, measures against water leakage are the most important.
By providing five stages of O-rings 64 in each of them and sealing them with the housing 53 on the rotating side, a seal with almost no water leakage is achieved, so that good turning continuous welding can be performed.

When the shape and dimensions of the nozzle 2 change, the radial direction is adjusted by the horizontal slide 5 and the inclination angle with respect to the nozzle axis is adjusted by the rotating mechanism of the wire projection length control slide 6. This makes it easy to respond.

Further, the copying of the torch height with respect to the lamination of the weld metal is performed by controlling the welding current by the length of the protruding wire.
By successively moving to the surface layer by the wire protrusion length control slide 6, lamination continuous welding can be continuously performed without interruption to the upper layer.

Further, in order to obtain a good shield against a narrow groove shape in a narrow place, the torch body 76 of the welding torch 7 has a shield nozzle 86 having an elliptical shape in the welding traveling direction.
By providing the shield, the shield in the groove can be kept good.

As described above, the setting can be simplified by adopting the one-touch fixing method to the inner surface of the nozzle, the torch position can be controlled by installing the lightweight and stable copying mechanism (using the arc current control), and one layer and one pass can be achieved by the narrow groove. The simplification of the lamination method has become possible, and it has become possible to shorten the welding operation time and reduce the number of steps.

[0070]

According to the nozzle MAG welding method of the present invention, a parallel narrow groove is formed around the nozzle, and the discharge of the shielding gas from the auxiliary shield ring toward the groove is started. The welding torch is turned around while rotating the welding torch while oscillating while drawing an arc at the tip of the welding wire with the rotation of the curve tip and the tip of the welding wire is turned around. The welding torch is rotated around the welding torch, and the welding metal is layered in the groove by repeating this. Since the vehicle is turned every time it is turned over, automatic MAG welding can be performed, and highly efficient welding can be performed.

Further, since the shielding gas is sprayed from the auxiliary ring toward the groove and welding is performed while drawing an arc at the tip of the welding wire, high quality welding can be performed.
Because of the continuous inversion welding, it is possible to simplify the device, to make it compact and robust, and to improve the reliability of the device.

In the nozzle MAG welding machine of the present invention, a clamp jig, a turning mechanism, a slip ring mechanism, a horizontal slide, a wire protrusion length control slide, a welding torch, and a wire feed mechanism are provided. By providing the welding machine, a welding machine that can be easily attached to the nozzle and can perform the above-described welding method is realized.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a welding apparatus applied to a nozzle MAG welding method according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a groove shape according to the embodiment.

FIG. 3 is an explanatory diagram of shield gas discharge according to the embodiment.

4A and 4B are explanatory diagrams of an oscillate at the tip of a welding wire according to the embodiment, wherein FIG. 4A is a side view, and FIG. 4B is a view taken along the line AA of FIG.

FIGS. 5A and 5B are explanatory diagrams of turning traveling of the welding torch according to the embodiment, wherein FIG. 5A is a plan view, FIG. 5B is a view taken along the line BB of FIG. FIG. 6D is a view taken in the direction of the arrows CC, (d) is an explanatory view just before the welding torch is inverted, and (e) is an explanatory view at the time of inversion.

FIG. 6 is a front view of a nozzle MAG welding machine according to one embodiment of the present invention.

FIGS. 7A and 7B are explanatory diagrams of an installation operation procedure of the nozzle MAG welding machine according to the embodiment, wherein FIG. 7A is an installation of a clamp jig, FIG. (D) is an explanatory diagram of arc start.

8A and 8B are explanatory views of the clamp jig according to the embodiment, wherein FIG. 8A is a side cross-sectional view and FIG. 8B is a view taken along the line DD of FIG.

FIG. 9 is a side sectional view of the turning mechanism according to the embodiment.

FIGS. 10A and 10B are explanatory views of the slip ring mechanism according to the embodiment, wherein FIG. 10A is a side sectional view, and FIG.

FIGS. 11A and 11B are explanatory views of a wire protrusion length control slide according to the embodiment, wherein FIG. 11A is a plan view and FIG.
FIG.

FIGS. 12A and 12B are explanatory diagrams of the MAG welding torch according to the embodiment, wherein FIG. 12A is a front view, FIG. 12B is a view taken along the line FF of FIG. FIG.

13A and 13B are explanatory diagrams of a boiler drum, wherein FIG. 13A is an overall side view, and FIG. 13B is an enlarged cross-sectional view of a portion H in FIG.

FIG. 14 is an explanatory view of a groove in a conventional welding method.

[Explanation of symbols]

 Reference Signs List 1 boiler drum 2 nozzle 3 groove 4 clamp jig 5 horizontal slide 6 wire protrusion length control slide 7 welding torch 8 tip 9 auxiliary shield ring 10 welding wire 11 torch rotation angle 12 oscillate width 13 weld metal 14 arc 15 traveling direction 16 Start point 17 Inversion position 18 Shield gas 20 Hollow shaft 22 Spur gear 24 Bearing 26 Base plate 28 Rotating motor 29,30 Bevel gear 31 Shaft 32 Spur gear 33,35 Proximity switch 40 Power cable 41 Power bolt 42 Power ring 43 Brush 44 Power ring 45 energizing shoe 46 energizing bolt 46 'energizing block 50 insulating flange 51 hollow rotor 52 bearing 57 hollow shaft 58 slip ring 64a-e O-ring 65 rotating plate 66 base plate 7 Vertical drive motor 69 Slider 73a, b, 74 Proximity switch 76 Torch main body 78 Inner tube 79 Torch inner cylinder 80 Torch outer cylinder 84 Curve chip 86a, b Shield nozzle 90 Rotary motor 91, 93 Timing pulley 96 Potentiometer 101 Cooling water supply pipe 102 Cooling water drain pipe and power supply cable 104 Swivel mechanism 105 Slip ring mechanism 106, 107 Shield gas supply pipe 109 Wire feed motor 110 Wire reel 111 Conduit cable 112 Clamp body 114 Shaft 116 Clamp piece 117 Tension coil spring

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI B23K 33/00 B23K 33/00 A (72) Inventor Shoji Kushimoto 2-1-1, Araimachi Shinhama, Takasago City, Hyogo Prefecture Mitsubishi Heavy Industries, Ltd. Inside the Takasago Research Laboratory (72) Inventor Tsutomu Masaki 2-1-1 Shinhama, Arai-machi, Takasago City, Hyogo Prefecture Inside the Takasago Research Laboratory Mitsubishi Heavy Industries, Ltd. (72) Inventor: Takehiko Imada, Takahama Research Institute, Takasago City, Hyogo Prefecture

Claims (5)

[Claims] 1. A parallel narrow groove formed around the nozzle installed on the member to be attached and inclined toward the center of the nozzle, and an auxiliary shield ring is provided on the surface of the member around the nozzle. Set up
A welding machine is arranged on the nozzle and the tip of a welding torch provided with a curve tip at the tip is inserted into the groove, and the discharge of the shielding gas from the auxiliary shield ring toward the groove is performed. After the start, adjust the oscillate width and the stop time at both ends to start the turning travel of the welding torch that turns around the nozzle while rotating the welding torch and oscillating the tip of the welding wire with the curve tip. Perform welding in the groove, stop the oscillate when the welding torch has completed one round, reduce the welding current and invert the welding torch, restart the oscillate after the inversion of the welding torch and return the reduced welding current The welding torch is swiveled in the opposite direction and the welding torch is repeatedly turned and inverted to repeatedly deposit the weld metal in the groove, and to the member to be mounted. The nozzle MAG welding method, which comprises carrying out the mounting of the platform. 2. A clamp jig inserted into the nozzle and fixed to the nozzle, a turning mechanism fitted and fixed to the clamp jig, a slip ring mechanism mounted on the upper part of the turning mechanism, and the turning mechanism. A horizontal slide attached to a side of the horizontal slide, a wire protrusion length control slide provided at one end of the horizontal slide, a welding torch provided at the wire protrusion length control slide, and the other end of the horizontal slide A nozzle MAG welding machine comprising a wire feeding mechanism mounted on a nozzle. 3. The nozzle MAG welding machine according to claim 2, wherein the turning mechanism is connected to a hollow shaft having a spur gear and connected to the clamp jig via a bearing and the hollow shaft. A base plate to which the horizontal slide is connected, a turning drive mechanism provided on the base plate and connected to the spur gear, and a turning position detection sensor provided on the base plate;
A nozzle MAG welding machine, comprising: a current-carrying part, a cooling water flow part, and a shield gas ventilation part. 4. The nozzle MAG welding machine according to claim 2, wherein the wire projection length control slide includes a rotating plate that changes an angle of attachment to the horizontal slide. Welding machine. 5. The nozzle MAG welding machine according to claim 2, wherein the welding torch is connected to the wire projection length control slide, a torch main body, an outer cylinder passing through the torch main body, and an outer cylinder. A tip provided at the tip of the torch, an inner cylinder provided in the outer cylinder through which a welding wire supplied to the curve tip passes, and a repetitive rotation of the outer cylinder provided on the torch body. A nozzle MAG welding machine comprising a rotary drive mechanism.