JP2003311481A - Welding equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide low-cost welding equipment in which the tensile residual stress of the surface of a weld zone is efficiently converted into compression. <P>SOLUTION: The welding equipment comprises: a torch 1 for Tungsten Inert Gas (TIG) welding supported on a carriage and connectable to a power source; an injection nozzle 21 supported on the carriage and supplying water to welded marks by means of the torch 1 for TIG welding; a suction nozzle 20 supported on the carriage and having a suction port at the outer periphery of the injection nozzle 21; a cooling medium supply hose 25 supplying water to the injection nozzle 21 by connecting the injection nozzle 21 to a water source; a suction pump providing suction force to the suction nozzle 20; and a container receiving the water sucked by means of the suction nozzle 20 through a cooling medium recovery hose 26 connected to the suction nozzle 20. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welding apparatus, and specifically, for example, converts tensile residual stress existing on the surface of a welded portion of stainless steel and nickel-base alloy steel into compressive residual stress. Therefore, the present invention relates to a welding device equipped with a device for supplying a cooling medium to a high temperature portion of a welding mark to quench immediately after welding.

[0002]

2. Description of the Related Art In stainless steel and nickel-base alloy steel,
Chromium carbide precipitates at the grain boundaries due to welding heat, etc., and as a result, a chrome deficient layer is formed in the immediate vicinity of the grain boundary, and this chrome deficient layer undergoes sensitization (a phenomenon in which sensitivity to corrosion increases). To do. In addition, since a high tensile residual stress generally exists on the surface near the welded portion, stress corrosion cracking occurs when the material is used in a severe corrosive environment in a sensitized state. That is, when the three factors of material sensitization, high tensile residual stress, and corrosive environment are superimposed, the risk of stress corrosion cracking increases.

By the way, various methods have been proposed in the past for reducing the high tensile residual stress that causes stress corrosion cracking, and there is a method of reducing the tensile residual stress simultaneously with welding.

For example, in Japanese Unexamined Patent Publication (Kokai) No. 10-34374, entitled "Method for Generating Residual Compressive Stress in Stainless Steel and Nickel Base Superalloy and Repair of Stress Corrosion Cracking by Underwater Welding", compression residual by underwater plasma transfer arc welding is performed. A method of generating stress is disclosed.
The technique disclosed in this publication uses a local drainage device that keeps water removed from the molten pool, thereby generating a compressive residual stress.

Further, for example, in Japanese Unexamined Patent Publication No. 8-155650, entitled "Welding Method for Austenitic Stainless Steels", when austenitic stainless steels are welded, they are cooled efficiently in a short time to prevent thermal strain and residual We have disclosed a technology to eliminate the generation of stress and to obtain a good quality weld with excellent corrosion resistance and durability.This technology discloses that at least one of the front and back surfaces of the weld immediately after welding is It cools by spraying solidified particles of carbon.

From the viewpoint of quenching the surface of the weld immediately after welding, in order to suppress the sensitization that causes stress corrosion cracking, for example, Japanese Patent Laid-Open No. 58-205687 discloses “Austenitic Stainless Steel”. Entitled "Welding method for steel and welding torch thereof", in welding austenitic stainless steel, after the weld metal is solidified, the weld metal part and the vicinity of the metal part are heated to a temperature range of 850 ° C to 1200 ° C. At this time, the weld metal portion and the vicinity of the metal portion are rapidly cooled with running water.

[0007]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
There are the following problems. First, in the conventional technology that generates compressive residual stress by underwater plasma transfer arc welding, construction in a state where sufficient water is spread around the periphery, such as repair welding inside the reactor pressure vessel filled with reactor water. Therefore, there is a problem that it is difficult to apply, for example, when repair is necessary when the reactor water is drained from the reactor pressure vessel.

[0008] Next, in the prior art in which carbon dioxide condensed solid particles are sprayed on at least one of the front and rear surfaces of the welded portion immediately after welding to cool, a facility for producing or storing the carbon dioxide condensed solid is provided. Will be needed for this,
There are problems that the device becomes complicated and cost is disadvantageous as compared with cooling by water.

Further, when the weld metal and the vicinity of the metal are heated to a temperature range of 850 ° C. to 1200 ° C. after the weld metal is solidified, the weld metal and the vicinity of the metal are rapidly cooled by running water. In the technology, there is a problem that the water used for quenching scatters at the welding work site and the workability deteriorates.

From the three factors of stress corrosion cracking, the above-mentioned problems in improving the stress corrosion cracking resistance of the welded portion and the heat affected zone of stainless steel and nickel-base alloy steel by improving the stress factor and the sensitizing factor. The points need to be resolved.

In view of the above-mentioned problems, an object of the present invention is that the cooling treatment required for converting the tensile residual stress on the surface of the welded portion into the compressive stress can be used in the air, the cost can be reduced, and the workability can be improved. It is to provide a welding device that does not damage it.

[0012]

Means for achieving the object of the present invention is to provide a welding apparatus provided with a welding torch and a cooling mechanism for supplying water to a portion welded by the welding torch. Is a welding device characterized by comprising a jet nozzle for supplying water to the welded part and a suction nozzle for sucking water supplied to the welded part. When rapidly cooling the region where the torch has passed, water is supplied as a cooling medium from the injection nozzle to the surface of the welded part to rapidly cool the welding trace, and the used water for quenching that has overflowed from the region immediately below the injection nozzle is sucked in. A method of welding is achieved by moving the suction nozzle while following the movement of the welding torch while collecting with a nozzle.

In such means, it is preferable that the suction port of the suction nozzle is provided around the outer periphery of the injection nozzle.

Further, when the suction port of the suction nozzle is provided around the outer periphery of the jet nozzle, it is preferable that the jet nozzle is provided inside the suction nozzle.

Further, it is preferable to provide a barrier between the welding torch and the suction nozzle, which obstructs suction by the suction nozzle.

Further, it is preferable that the suction nozzle and the injection nozzle are integrally connected to form an integrated body, and the integrated body is equipped with a wheel for rolling an object to be welded.

Further, it is preferable that the suction nozzle, the injection nozzle, and the welding torch are supported by a common moving body.

Further, when the welding direction is the vertical direction, it is preferable that the suction nozzle is equipped with a packing projecting toward the object to be welded along the periphery of the suction nozzle.

Further, it is preferable that the portion of the suction nozzle adjacent to the surface of the object to be welded has a shape along the shape of the object to be welded after welding.

Further, in the case of the welding work of the pipe, it is preferable that the portion adjacent to the pipe surface of the suction nozzle is molded in a partial arc shape along the pipe surface which is the object to be welded.

Further, a welding torch supported by a movable body and connectable to a power source, an injection nozzle which is supported by the movable body and supplies water to a welding mark by the welding torch, and a welding torch supported by the movable body are provided. A suction nozzle having a suction port around the outer periphery of the jet nozzle, a hose that connects the jet nozzle and a water source to supply water to the jet nozzle, a suction pump that applies a suction force to the suction nozzle, and It is easy and preferable in handling of water to use a welding device having a container that receives water sucked by a nozzle through a hose connected to the nozzle.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Regarding the welding apparatus according to the present invention,
The first embodiment will be described in detail with reference to FIGS. 1, 2, and 3. FIG. 1 is a first embodiment according to the present invention, which is an apparatus for applying a final layer of a flat plate butt joint. The TIG welding torch 1 is used as a welding torch and welding is performed while supplying the wire 3.

Reference numeral 30 is a support mechanism upper support plate installed on the carriage, and the TIG welding torch 1 is installed via the torch support mechanism 10 on the weaving device 11 installed on the support mechanism upper support plate 30 on the carriage. ing. Here, the weaving device 11 is a device for swinging the support beam 12 protruding in the vertical direction with respect to the paper surface in FIG. 1 in the vertical direction of the paper surface, and by using this device, a wide width can be obtained by a single construction. Welding becomes possible. A wire tip 4 is attached to the TIG welding torch 1 via a wire tip supporting mechanism 5.

A conduit cable 6 is attached to the wire tip 4.
The welding metal wire 3 is supplied from the wire supply device via the. Here, the TIG welding torch 1 is a known one, and a current is supplied to the tungsten electrode 2 via a current torch cable 7. Further, argon gas is supplied through the torch hose 8 for argon gas, and the gas nozzle 1
Eject from 3. This argon gas becomes an atmosphere of an arc generated during welding work, and has an effect of preventing impurities in the surrounding atmosphere from entering the weld metal portion. Further, in order to prevent the heating of the torch, the cooling water circulates through the cooling water torch hose 9 so as to remove the heat of the TIG welding torch 1 and cool it.

Reference numeral 21 denotes a water injection nozzle, which is supplied with water from a flexible cooling medium supply hose 25 and ejected from a perforated plate 22. One end of the cooling medium supply hose 25 is connected to the injection nozzle 21, and the other end is connected to a water source via a pump. The water source equipment may be a tank for storing purified water or other equipment. Reference numeral 20 denotes a suction nozzle, which is installed so as to include the ejection nozzle 21 therein. A suction port 23 is provided between the ejection nozzle and the suction nozzle, and the flexible cooling medium recovery hose 26 is sucked. The ejection nozzle 21 is connected to the suction nozzle 20 via a jig 28.
The suction nozzle 20 is fixed to the support mechanism upper support plate 30 via the cooling device support mechanism 27. Therefore, the carriage including the support mechanism upper support plate 30 constitutes a moving mechanism.

As shown in FIGS. 1 and 2, the suction nozzle 20 is equipped with wheels 24 at four positions so as to be able to roll on the upper surface of the structure 40 to be welded, and the upper surface of the structure 40 to be welded and the suction nozzle 20. A constant gap is maintained between the lower end of the suction nozzle 20 and the lower end of the suction nozzle 20 to prevent excessive suction of the atmosphere outside the suction nozzle 20, or to prevent water used for cooling from leaking easily.

A shield 19 is fixed to the portion of the suction nozzle 20 facing the TIG welding torch 1, and the shield 19 is fixed.
Has a lower end in contact with the upper surface of the structure 40 to be welded. The shield 19 is in the form of a metal brush made of, for example, an ultrafine wire made of stainless steel, and the lower end of the shield 19 is flexible to be welded to the structure 4
Following the shape of the upper surface of 0, the shield 19
Function as a barrier that obstructs the suction of the atmosphere from the TIG welding torch 1 side to the. Therefore, when suction is performed by the suction nozzle 20, the turbulence of the air flow in the direction in which the TIG welding torch 1 is located is reduced, and an arc can be stably generated.

FIG. 2 shows the injection nozzle 21 from the direction in which the perforated plate 22 can be seen. A perforated plate 22 is attached to the injection nozzle 21.
A hole 29 for injecting a cooling medium is formed in the hole. The injection nozzle 21 is installed inside the suction nozzle 20. The gap between the injection nozzle 21 and the suction nozzle 20 is the suction port 23.
become. The jet nozzle 21 is connected to a cooling medium supply hose 25 for passing water sent by a pump (not shown), and the jet nozzle 21 is supplied with water sent through the cooling medium supply hose 25. The supplied water is sprayed onto the structure 40 to be welded through the hole 29 of the perforated plate 22, contacts the welding trace immediately after welding with the TIG welding torch 1, and cools the welding trace. The welding trace is made free of tensile stress, and preferably has compressive stress.

The water thus injected partially evaporates, and part of the water is not completely evaporated and remains on the surface of the structure 40 to be welded. Inside the suction nozzle 20, a negative pressure, that is, a suction force is generated by the pump 122 via the cooling medium recovery hose 26. Therefore, the water remaining on the surface of the structure 40 to be welded, particularly on the surface of the welded portion without being evaporated or completely evaporated, is sucked from the suction port 23. Injection nozzle 21
Is contained in the suction nozzle 20, the water ejected from the ejection nozzle 21 is stored in the container through the cooling medium recovery hose 26 from the suction nozzle 20 even if the water evaporates into water vapor or does not evaporate. It is collected in a certain water tank 120 and does not leak out of the suction nozzle 20. Therefore, the water jetted for cooling does not scatter to the surroundings and further does not enter under the TIG welding torch 1. This makes it possible to perform welding without containing impurities in the welded portion.

FIG. 3 is a diagram showing the overall configuration of the first embodiment. Current is supplied to the TIG power supply 101 from the power supply panel 103 via the input cable 106. Further, cooling water is supplied from the water cooling circulation device 104 to the TIG power supply 101 via the water cooling hose 107. further,
Argon gas is supplied to the TIG power supply 101 from the argon gas cylinder 105 via the gas hose 108.
The electric current, the cooling water, and the argon gas supplied to the TIG power supply 101 are controlled by the control device in the TIG power supply 101 and communicate with the cable and the hose of the torch cable 109.

The torch cable 109 is used for the TIG power source 10
1 and the TIG welding torch 1 are bundled with a cable and a hose, and are composed of a current torch cable, an argon gas torch hose 8 and a cooling water torch hose 9. For the torch cable for electric current, TIG welding power source 1
The torch 1 for TIG welding has a current generated by being controlled by 01.
Sent to. Argon gas supplied from the argon gas cylinder 105 is supplied to the torch hose for argon gas as TI.
Under the control of supply and stop within the G welding power source 101, it is supplied to the TIG welding torch 1 side during supply control. The cooling water from the water cooling circulation device 104 is supplied to the cooling water torch hose in the TIG welding power source 101 under the control of supply and stop, and is supplied to the TIG welding torch 1 side during supply control.

The structure 40 to be welded has a ground cable 1
It is installed with a power source through 11. A current detector is attached to the ground cable, and the measured value of the current is the control device 102.
Is taken into. A welding power source remote controller 114 and a wire feeder remote controller 115 are attached to the controller 102 via a remote controller cable 113. A wire feeding device 121 is attached via a control cable 117, and a torch switch 119 is further connected from the wire feeding device 121 via a torch switch cable 118.
Is attached. The wire 3 is fed from the wire feeding device 121 through the conduit cable 6 to the TIG welding torch 1.

Support mechanism upper support plate 3 provided on the carriage 31
0, a weaving device 11 is installed, and is connected to a weaving control device 110 via a control cable. Electric power is supplied to the weaving control device 110 via the input cable 106. A TIG welding torch is installed from the weaving device 11 via the torch support mechanism 10. The suction nozzle 20 is installed on the support mechanism upper support plate 30 provided on the carriage 31 via the cooling device support mechanism 27. Further, a moving mechanism remote controller 116 that controls traveling of the carriage 31 is connected to the carriage 31 by a remote control cable 113.

One end of a cooling medium recovery hose 26 is attached to the suction nozzle 20, and the water of the cooling medium recovered by suction has the other end of the cooling medium recovery hose 26 in a water tank.
Since it is open and connected to 120 gas phase regions, aquarium 1
It stays at 20. Further, in order to perform suction, a suction pump 122 is installed with a suction port connected to the gas phase region of the water tank 120. An injection nozzle 21 is installed inside the suction nozzle 20, and a cooling medium is supplied via a cooling medium supply hose 25.

Next, the welding operation according to this embodiment will be described. T at the position where welding of the structure 40 to be welded is performed.
Install the torch 1 for IG welding. Welding power remote control 11
From 4, set the current and voltage conditions corresponding to the welding conditions.
Further, the wire feeding amount is set from the wire feeding device remote controller. The control device 102 is set to supply a current corresponding to the input from the welding power source remote controller 114 to the TIG welding torch 1. Also, the wire feeding device remote controller 1
Settings for supplying the wire input from 15 are made. Weaving conditions are input to the weaving controller 110 to start weaving. Further, the moving speed of the carriage 31 is input from the moving mechanism remote controller 116.

When the above preparation is completed, the torch switch 119 is turned on. Since the torch switch 119 ON signal is also transmitted to the control device 102 via the wire feeding device 121, the wire feeding device 121, and the control cable 117, the TIG power supply 1 controlled by the control device 102 is controlled.
From 01, a current is supplied to the TIG welding torch 1 to generate an arc, and the wire feeder 121 operates to start wire feeding. Since the supply of water to the jet nozzle 21 and the suction operation of the suction nozzle 20 by the pump 122 have already been started, the region which has become hot due to the welding using the TIG welding torch 1 is rapidly cooled immediately after welding.
The quenching immediately after welding refers to the time range immediately after welding which is the temperature range of the welding mark effective for improving the stress of the welding mark. Further, during the rapid cooling, the water of the cooling medium does not leak out of the suction nozzle, and even if suction is performed, the TI
Since the air flow immediately below the G welding torch 1 is not disturbed, it is possible to perform high quality welding.

When the welding is completed, the torch switch 119 is turned off to stop the arc from the TIG welding torch 1. From the control device 102 to the wire feeding device 121
A stop signal is issued to stop the wire feeding. Dolly 31
To stop. Further, the supply of the cooling medium is stopped, and finally the suction pump 122 is stopped. This completes the work.

A second embodiment of the present invention will be described with reference to FIG. FIG. 4 shows a case where the welding method of the present invention is applied to the construction of the structure 201 to be welded which needs to be welded in the vertical direction. It is an embodiment in the case of performing welding by moving upward (toward a high portion from a low portion) with respect to a welding line in the vertical direction. If the surface to be welded is vertical, the suction of the suction nozzle 20 may not completely recover the water of the cooling medium.

In this embodiment, in order to prevent the cooling medium from leaking to the outside of the suction nozzle, the suction nozzle 2
The packing 202 is provided on the outer periphery of 0 to carry out. The packing 202 is the structure to be welded 4 from the outer circumference of the suction nozzle 20.
It is suppressed as much as possible that the water sticks out to the surface of 0 and leaks to the outside of the suction nozzle 20. As the packing material,
A flame-retardant fabric is suitable so as to withstand heat generated during welding such as an arc emitted from the TIG welding torch 1. By applying the suction nozzle of the present embodiment and the other procedure being the same as in the first embodiment, it is possible to rapidly cool the surface of the welded portion immediately after welding even in the case of vertical welding. The water of the cooling medium does not leak out of the suction nozzle, and the air flow near the electrodes is not disturbed even if suction is performed, so that high quality welding can be performed. Further, it becomes possible to generate a compressive residual stress on the surface of the welded portion.

A third embodiment of the present invention will be described with reference to FIG. FIG. 5 shows a case where the welding method of the present invention is applied to the construction of the fillet welded portion 211. In this embodiment,
In order to prevent water of the cooling medium from leaking to the outside of the suction nozzle 20 at the fillet weld, the outer shape of the tip side portion 212 of the suction nozzle 20 matches the shape of the corner of the fillet weld. The shape is such that it follows the welding trace after welding and the surface of the structure 40 to be welded that is combined at right angles. By applying the suction nozzle 20 of the present embodiment and by making the other procedures the same as in the first embodiment, it is possible to rapidly cool the surface of the welded portion immediately after welding during fillet welding. The water of the cooling medium does not leak out of the suction nozzle, and the air flow near the electrodes is not disturbed even if suction is performed, so that high quality welding can be performed. Further, it becomes possible to generate a compressive residual stress on the surface of the welded portion.

A fourth embodiment of the present invention will be described with reference to FIG. FIG. 6 shows the case where the welding method of the present invention is applied to the construction of the circumferential welded portion of the pipe 221 which is the object to be welded. In the present embodiment, in order to prevent water of the cooling medium from leaking to the outside of the suction nozzle 20 at the welded portion, the outer shape of the tip portion 222 of the suction nozzle 20 has a partial arc shape that matches the curvature of the outer surface of the pipe 221. This is carried out using a suction nozzle having a tip shape. The tip portion of the injection nozzle 21 also has a similar tip shape. By applying the suction nozzle 20 of the present embodiment and by making the other procedures the same as in the first embodiment, it is possible to rapidly cool the welded part surface immediately after welding even during pipe welding, and at that time, Water of the cooling medium does not leak to the outside of the suction nozzle, and even if suction is performed, the air flow near the electrodes is not disturbed, so that high quality welding can be performed. Further, it becomes possible to generate a compressive residual stress on the surface of the welded portion.

The first to fourth embodiments described above are embodiments in which the structure to be welded is fixed and the torch 1 for TIG welding and the nozzles 20 and 21 move synchronously at the same speed. However, even if the TIG welding torch and the nozzles 20 and 21 are fixed in advance and welding is performed while moving the structure 40 to be welded, there is no problem in applying the method of the present invention.

Although the TIG welding was used as the welding method, the MIG welding, the MAG welding, and the covered arc welding can also be rapidly cooled immediately after the welding by using the method of the present invention. There is no leakage of the cooling medium to the outside of the nozzle and no deterioration in quality. Further, it becomes possible to generate a compressive residual stress on the surface of the welded portion.

According to each embodiment of the present invention, during welding,
By simply moving the moving mechanism, the cooling medium is sprayed onto the weld surface, and the excess cooling medium remaining on the weld surface is collected from the suction nozzles arranged around the spray nozzle. Therefore, the cooling medium is prevented from leaking and scattered to improve workability. Further, at this time, by making the shape of the suction nozzle in close contact with the structure to be welded, suction of the cooling medium becomes dominant, and the cooling medium can be collected by suction without disturbing the air flow near the arc. . Furthermore, by using a welding torch having a gas shielded electrode, the cooling medium caught inside the arc is reduced, and good weldability can be secured. Further, since water is used as the cooling medium, the apparatus price is cheaper and more economical than the one using condensed solid particles of carbon dioxide as the cooling medium.

[0045]

As described above, according to the present invention, workability and economic efficiency can be improved in a welding apparatus equipped with means for cooling the weld trace immediately after welding to improve the stress.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a first embodiment of a welding device according to the present invention.

FIG. 2 is a detailed explanatory diagram of an injection nozzle, a suction nozzle, and a suction port in the first embodiment.

FIG. 3 is an explanatory diagram showing an overall configuration of a welding device of the present invention.

FIG. 4 is an explanatory view showing a second embodiment of the welding device according to the present invention.

FIG. 5 is an explanatory view showing a third embodiment of the welding device according to the present invention.

FIG. 6 is an explanatory diagram showing a fourth embodiment of a welding device according to the present invention.

[Explanation of symbols]

1 ... TIG welding torch, 2 ... tungsten electrode, 3 ...
Wire, 4 ... Wire tip, 5 ... Wire tip support mechanism, 6 ... Conduit cable, 7 ... Current torch cable, 8 ... Argon gas torch hose, 9 ... Cooling water torch hose, 10 ... Torch support mechanism, 11 ... Weaving device, 12 ... Support beam, 13 ... Gas nozzle, 19 ... Shield, 20 ... Suction nozzle, 21 ... Injection nozzle, 22 ... Perforated plate, 23 ... Suction port, 24 ... Wheel, 25 ... Cooling medium supply hose, 26 ... Cooling medium recovery hose, 27 ... Cooling device support mechanism, 28 ... Jig, 29 ... Hole, 30 ... Support mechanism upper support plate, 31 ... Cart moving mechanism, 32 ... Moving mechanism remote controller,
40, 201 ... Structure to be welded, 101 ... TIG welding power source, 102 ... Control device, 103 ... Power board, 104 ... Water cooling circulation device, 105 ... Argon gas cylinder, 106 ... Input cable, 107 ... Water cooling hose, 108 ... Gas hose,
109 ... Torch cable, 110 ... Weaving control device, 111 ... Ground cable, 113 ... Remote control cable, 114 ... Welding power source remote control, 115 ... Wire feeding device remote control, 116 ... Moving mechanism remote control, 117 ... Control cable, 118 ... Torch switch Cable 119 ...
Torch switch, 120 ... Water tank, 121 ... Wire feeding device, 122 ... Suction pump, 202 ... Packing, 211 ...
Fillet welds, 212 ... Attachments for fillet welds, 22
1 ... Piping.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kunio Enomoto             4-6 Kanda Surugadai, Chiyoda-ku, Tokyo             Hitachi Engineering Consulting Co., Ltd.             Inside the company (72) Inventor Hideya Ansai             3-1-1 Sachimachi, Hitachi City, Ibaraki Prefecture Stock Association             Hitachi, Ltd. Nuclear Business Division (72) Inventor Mitsuo Kawakami             Hitachi 2-3-1, Saiwaicho, Hitachi-shi, Ibaraki             Engineering Co., Ltd. (72) Inventor Hiroshi Tsujimura             3-1-1 Sachimachi, Hitachi City, Ibaraki Prefecture Stock Association             Hitachi, Ltd. Nuclear Business Division

Claims (10)

[Claims] 1. A welding apparatus comprising a welding torch and a cooling mechanism for supplying water to a portion welded by the welding torch, wherein the cooling mechanism includes an injection nozzle for supplying water to the welded portion, A welding device comprising: a suction nozzle for sucking water supplied to a welded portion; 2. The welding device according to claim 1, wherein the suction port of the suction nozzle is provided around the outer periphery of the injection nozzle. 3. The welding apparatus according to claim 2, wherein the injection nozzle is provided inside the suction nozzle. 4. The welding device according to claim 3, further comprising a barrier between the welding torch and the suction nozzle, which is a barrier to suction by the suction nozzle. 5. The apparatus according to claim 3, wherein the suction nozzle and the injection nozzle are integrally combined to form an integrated body, and the integrated body is equipped with wheels for rolling a workpiece. Welding equipment. 6. The welding apparatus according to claim 5, wherein the suction nozzle, the injection nozzle, and the welding torch are supported by a common moving body. 7. The welding apparatus according to claim 3, wherein the suction nozzle is equipped with a packing projecting toward the object to be welded along the periphery of the suction nozzle. 8. The welding apparatus according to claim 3, wherein the portion of the suction nozzle adjacent to the surface of the object to be welded has a shape along the shape of the object to be welded after welding. 9. The welding device according to claim 3, wherein a portion of the suction nozzle adjacent to the pipe surface is molded in a partial arc shape along the pipe surface which is the object to be welded. 10. A welding torch supported by a moving body and connectable to a power source, an injection nozzle which is supported by the moving body and supplies water to a welding mark formed by the welding torch, and a welding torch supported by the moving body. A suction nozzle having a suction port around the outer periphery of the jet nozzle; a hose that connects the jet nozzle and a water source to supply water to the jet nozzle; a suction pump that applies a suction force to the suction nozzle; And a container that receives water sucked by a nozzle through a hose connected to the nozzle.