JP5941417B2 - Pipe welding method - Google Patents

Description

The present invention relates to a piping welding method, in particular, it relates to suitable piping welding method for application to welding of the nuclear power plant piping.

  When two pipes are butt-welded, it is required to accurately match the groove of the two pipes to be butt for welding. For the groove alignment of the pipes to be welded, it has been proposed to use, for example, a pipe groove assembling apparatus described in JP-A-2002-1585.

  The pipe groove assembling apparatus described in Japanese Patent Application Laid-Open No. 2002-1585 has two annular clamp jigs, and a plurality of clamps that can move in the radial direction are provided in the clamp body of each clamp jig. Bolts are provided at predetermined intervals. A clamp pad that contacts the inner surface of the pipe to be welded is attached to the tip of each clamp bolt. Furthermore, a plurality of attracting means are provided at six locations in the circumferential direction on one end face of one clamp body. In one end surface of the other clamp body, six fitting holes are formed in the circumferential direction.

  As shown in FIG. 4 of Japanese Patent Laid-Open No. 2002-1585, one clamp body in which each clamp bolt is retracted is inserted into this pipe at the end face on the welding side of one pipe to which the clamp bolt is welded. . Thereafter, the clamp bolts of the clamp body are protruded in the radial direction, the clamp pad is brought into contact with the inner surface of the pipe, and the clamp body is mounted in the pipe. At this time, the axis of the clamp body and the axis of the pipe are coaxial. Another clamp body is similarly mounted in this pipe at the welding side end face of the other pipe. Two pipes are arranged with the end surfaces on the welding side facing each other, that is, with the two clamp bodies facing each other. Each drawing means provided in one clamp body is inserted into each fitting hole formed in the other clamp body, and the other clamp body is drawn by the drawing means. As a result, the gap between the groove pipes formed at the weld ends of the two pipes is adjusted, and the axes of these pipes are coaxial.

  A clamping jig described in Japanese Patent Laid-Open No. 4-89198 has a first frame body and a second frame body connected by a connecting body, and an air cylinder is attached to the first frame body and the second frame body. Yes. The first piston rod is connected to a first piston provided in an air cylinder attached to the first frame. A 2nd piston rod is connected with the 2nd piston provided in the air cylinder attached to the 2nd frame. Further, the clamp jig has a first clamp head and a second clamp head. Each of the first clamp head and the second clamp head has a plurality of (for example, three) arcuate bodies. Each arcuate body of the first clamp head is arranged around the first frame body so as to surround the first frame body, and is attached to a plurality of (for example, three) first link mechanisms attached to the first piston rod. . Each arcuate body of the second clamp head is disposed around the second frame body so as to surround the second frame body, and is attached to a plurality of (for example, three) second link mechanisms attached to the second piston rod. . Grooves extending in the circumferential direction of the first frame are formed on the outer surface that contacts the inner surface of the pipe of each arc-shaped body of the first clamp head. A gas supply passage communicating with the groove is formed in the arc-shaped body of the first clamp head and the first link mechanism.

  The second frame body of the clamp jig is inserted into one of the two pipes connected by welding. The second piston rod and the second link mechanism are moved to bring each arcuate body of the second clamp head into contact with the inner surface of the pipe, and the second frame is fixed to the pipe. At this time, it arrange | positions so that the end surface by the side of the groove | channel which made each arc-shaped body of a 2nd clamp head contact may be on the groove | channel formed in each arc-shaped body of a 1st clamp head. Thereafter, the first frame body is inserted into another pipe, and the arc-shaped bodies of the first clamp head are brought into contact with the inner surfaces of the two pipes by the movement of the first piston rod and the first link mechanism. The auxiliary clamp head is disposed between the arcuate bodies of the first clamp head in the circumferential direction of the first frame body, and closes the gap between the arcuate bodies.

  In this state, the inert gas is supplied to the groove from the gas supply passage, and the inside of each groove formed in each arcuate body in contact with the inner surfaces of the groove portions of the two pipes is filled with the inert gas. . Thereafter, the two pipes are welded and joined.

  An internal clamping device for pipe welding described in JP-A-4-200787 is described. This clamp device has two clamp bodies attached to one center shaft. Each clamp body has a cylinder, a piston, a piston rod, and a plurality of clamps. The piston is disposed in the cylinder, and a piston rod attached to the piston is slidably attached to the center shaft. The center shaft passes through the piston rod. Each clamp is attached to the piston rod via a link and extends from the piston rod in the radial direction of the cylinder. Each clamp has a roller member attached to the tip. Each clamp of the two clamp bodies is opposed in the axial direction of the center shaft. A plurality of cylinders attached to the center shaft are disposed between two clamp bodies, and a backing material is provided on a piston rod driven by the cylinders. The backing material is disposed between the roller member of one clamp body and the roller member of one clamp body.

  Each clamp body is inserted separately into two pipes to be welded, and the piston rod and the link are driven to bring the roller member of each clamp body into contact with the inner surface of each pipe. Since each clamp main body is attached to one center shaft, the two pipes are aligned by the contact of the roller members with the inner surface of each pipe. Thereafter, a plurality of backing materials arranged in the circumferential direction of the pipe are brought into contact with the back surface of the groove of each pipe at the welded portion, and then the two pipes are welded.

Japanese Patent Laid-Open No. 2002-1585 Japanese Patent Laid-Open No. 4-89198 JP-A-4-200787

  In the case of using the pipe groove assembling apparatus described in Japanese Patent Laid-Open No. 2002-1585, after the drawing means provided on one clamp body is inserted into the fitting hole formed on the other clamp body The other clamp body is pulled by the pulling means, the two clamp bodies are made coaxial, the distance between the two pipes to be welded is adjusted, and these pipes are aligned. For this reason, it takes time to insert the drawing means provided in one clamp body into the fitting hole formed in the other clamp body.

  In the internal clamp device for pipe welding described in Japanese Patent Laid-Open No. 4-200867, since each clamp body is attached to one center shaft, the two pipes can be easily aligned. It is difficult to adjust the interval between the two pipe grooves. The clamp jig described in Japanese Patent Laid-Open No. 4-89198 is also difficult to adjust the distance between the grooves of the two pipes to be welded.

An object of the present invention, the centering of the pipe can be accurately performed, it is to provide a piping welding method that can shorten the time required for adjustment of the spacing between the groove.

The features of the present invention that achieve the above-described object are as follows:
A connecting rod ;
A first clamp support portion attached to the connecting rod, a plurality of first pressing members that surround the first clamp support portion and are arranged in the circumferential direction of the first clamp support portion, and are attached separately to the first pressing member. A first clamp device provided on the first clamp support portion and having a first moving device for moving the first pressing member in the radial direction of the first clamp support portion;
A second clamp support portion attached to the connection rod so as to be movable in the axial direction of the connection rod; a plurality of second pressing members disposed around the second clamp support portion and disposed in the circumferential direction of the second clamp support portion; A second clamping device having a second moving device that is separately attached to the two pressing members and is provided on the second clamp support portion and moves the second pressing member in the radial direction of the second clamp support portion ;
A cylindrical member surrounding the connecting rod is attached to any one of the side surfaces of the first clamp support portion and the second clamp support portion facing each other,
The groove | channel which has the shape of the longitudinal cross-section of a cylindrical member in which the front-end | tip part of a cylindrical member is inserted is a clamp support part to which the cylindrical member of the 1st clamp support part and the 2nd clamp support part is not attached. , Formed on the side facing the tip of the cylindrical member,
An annular first elastic member that expands and contracts in the radial direction of the first clamp support portion has an inner end portion attached to the first clamp support portion and an outer end portion attached to each first pressing member. ,
An annular second elastic member that expands and contracts in the radial direction of the second clamp support portion has an inner end portion attached to the second clamp support portion and an outer end portion attached to each second pressing member. ,
A plurality of through holes are formed in the second clamp support portion outside the cylindrical member,
All the first pressing members respectively form first projecting portions projecting in the circumferential direction at both ends in the circumferential direction of the first clamp support portion, and are adjacent to each other in the circumferential direction of the first clamp support portion. Between the first pressing members, the first protrusion formed on one first pressing member and the first protrusion formed on the other first pressing member overlap in the axial direction of the connecting rod; and
All the second pressing members respectively form second projecting portions projecting in the circumferential direction at both ends in the circumferential direction of the second clamp support portion, and are adjacent to each other in the circumferential direction of the second clamp support portion. In the second pressing members, the second protrusion formed on one second pressing member and the second protrusion formed on the other second pressing member overlap in the axial direction of the connecting rod.
Using a pipe welding support device,
Insert the first clamping device into the first pipe,
Each first moving device presses each first pressing member against the inner surface of the first pipe to fix the first clamping device in the first pipe,
Insert the second clamping device into the second pipe to be welded with the first pipe,
Each second moving device presses each second pressing member against the inner surface of the second pipe to fix the second clamping device in the second pipe,
The second clamp support part is moved to the first clamp device side along the connecting rod and between the groove formed in the first pipe and the groove formed in the second pipe facing the groove. Adjust the interval,
After adjusting the gap interval, the second clamp support portion is formed in an annular space formed between the first clamp device and the second clamp device and between the tubular member, the first pipe, and the second pipe. Supplying inert gas through the through-holes,
While supplying an inert gas to the annular space, welding the first pass to join the first pipe and the second pipe,
The remaining welding of the first pipe and the second pipe, which is performed after the first pass welding , is to be performed while supplying the cooling medium to the annular space through the through hole .

Since the first clamp support portion attached to the connecting rod and the second clamp support portion attached to the connecting rod so as to be movable in the axial direction of the connecting rod are provided, the first clamp device is inserted into one pipe. Then, each first pressing member was pressed against the inner surface of each pipe, the second clamping device was inserted into another pipe welded to each pipe, and each second pressing member was pressed against the inner surface of each pipe. Sometimes, the two pipes can be accurately aligned. Moreover, since the 2nd clamp apparatus which has a 2nd clamp support part can be moved to the 1st clamp apparatus side along a connecting rod, the time required for the adjustment of the space | interval between the groove | channels of two piping is made to the precision of centering. It can be shortened while holding.
Furthermore, since the first pass welding for joining the first pipe and the second pipe is performed while supplying the inert gas to the annular space, the inner surface of the welded portion of the first pass of the first pipe and the second pipe is oxidized. Can be prevented. Further, since the remaining welding after the first pass welding is performed while supplying the cooling medium to the annular space through the through hole, the residual stress on the inner surface of the welded portion of the first pipe and the second pipe and the heat affected zone is improved It is possible to apply compressive residual stress to the inner surface of the welded portion and the heat affected zone of the first pipe and the second pipe. For this reason, generation | occurrence | production of the stress corrosion crack in the welding part and heat affected zone of 1st piping and 2nd piping can be prevented.

  ADVANTAGE OF THE INVENTION According to this invention, in the welding of piping, the center alignment of the piping to be welded can be performed accurately, and the time required for adjusting the space | interval between groove | channels can be shortened.

It is a longitudinal cross-sectional view (II sectional drawing of FIG. 2) of the pipe welding assistance apparatus used for the pipe welding method of Example 1 which is one suitable Example of this invention. It is an II-II arrow line view of FIG. It is the III-III arrow line view of the piping welding assistance apparatus shown in FIG. In the piping welding method of Example 1, it is explanatory drawing which shows the state which fixed one clamp apparatus of the piping welding assistance apparatus shown in FIG. 1 in one piping. In the piping welding method of Example 1, it is explanatory drawing which shows the state which fixed the other clamp apparatus of the piping welding assistance apparatus shown in FIG. 1 in the other piping. It is explanatory drawing which shows welding of the 1st path | pass of piping in the piping welding method of Example 1. FIG. In the piping welding method of Example 1, it is explanatory drawing which shows removal of each clamp apparatus of a piping welding assistance apparatus after welding. It is a characteristic view which shows distribution of the axial residual stress in the piping inner surface when not installing and installing a clamp apparatus inside. It is a characteristic view which shows distribution of the residual stress of the circumferential direction in the piping inner surface when not installing and installing a clamp apparatus inside. It is a characteristic view which shows distribution of the residual stress of the axial direction in the piping inner surface when not performing it with water cooling. It is a characteristic view which shows distribution of the residual stress of the circumferential direction in the piping inner surface when not performing it with water cooling. It is explanatory drawing which shows the pipe welding method of Example 2 which is another suitable Example of this invention. It is a characteristic view which shows distribution of the residual stress of the axial direction in the pipe inner surface at the time of pipe expansion without pipe expansion. It is a characteristic view which shows distribution of the residual stress of the circumferential direction in the piping inner surface at the time of pipe expansion without pipe expansion. It is explanatory drawing which shows the pipe welding method of Example 3 which is another suitable Example of this invention.

  Examples of the present invention will be described below.

  A pipe welding method according to embodiment 1, which is a preferred embodiment of the present invention, will be described with reference to FIGS.

  First, a pipe welding support device used in the pipe welding method of this embodiment will be described with reference to FIGS. The pipe welding support device 1 includes clamping devices 2 and 11, a cylindrical member 10, and a connecting shaft (connecting rod) 18.

  The clamp device (second clamp device) 11 includes a disc-shaped clamp support portion (second clamp support portion) 12, arc-shaped pressing members (second pressing members) 13a, 13b, 13c, 13d, and actuators (second (Moving device) 15a, 15b, 15c, 15d and a ring-shaped elastic member 20. The connecting shaft 18 passes through the center of the clamp support 12. A screw hole is formed at the center of the clamp support portion 12. The screw hole of the clamp support portion 12 is engaged with a screw 19 formed on the connection shaft 18, and the clamp support portion 12 is attached to the connection shaft 18. The screw 19 is formed up to the end of the coupling shaft 18 on the clamp support portion 12 side. A handle 36 for rotating the connecting shaft 18 is attached to the end of the connecting shaft 18 where the screw 19 is present. The connecting shaft 18 can be automatically rotated by using a motor instead of the handle 36. In this case, for example, a motor is installed on the outer side surface of the clamp support portion 3, and a gear that protrudes outward from the outer side surface and meshes with a gear attached to the end of the connecting shaft 18 is formed on the outer side surface. What is necessary is just to attach to the rotating shaft of the installed reduction gear, and just connect this rotating shaft to the rotating shaft of a motor. The actuators 15 a, 15 b, 15 c, and 15 d are provided on the outer peripheral portion of the clamp support portion 12 and are arranged at equal intervals in the circumferential direction of the clamp support portion 12.

  The pressing members 13 a, 13 b, 13 c, and 13 d are disposed to face the outer peripheral surface of the clamp support portion 12 in the radial direction of the clamp support portion 12, and surround the clamp support portion 12. The pressing members 13a, 13b, 13c, and 13d are arranged in the order of the pressing member 13a, the pressing member 13b, the pressing member 13c, and the pressing member 13d in the circumferential direction of the clamp support portion 12. The holding portion 14a of the pressing member 13a is connected to the actuator 15a. The holding portion 14b of the pressing member 13b is connected to the actuator 15b. The holding portion 14c of the pressing member 13c is connected to the actuator 15c. The holding portion 14d of the pressing member 13d is connected to the actuator 15d.

  As shown in FIG. 3, two arc-shaped projections 21 extending in the circumferential direction are respectively formed at both ends of the pressing member 13a in the circumferential direction of the clamp support portion 12, and the grooves 22 are formed by these projections. 21 is formed. The width of these protrusions in the radial direction of the clamp support portion 12 is the same as the width of the pressing member 13 in the radial direction of the clamp support portion 12. As shown in FIG. 3, two arc-shaped projections 23 extending in the circumferential direction are formed at both ends of the pressing member 13 d in the circumferential direction of the clamp support portion 12, and the grooves 24 form these projections 23. Is formed between. The protrusion 21 existing at one end of the pressing member 13a is inserted into a groove 24 formed at the opposite end of the pressing member 13d, and the protrusion 23 at the end of the pressing member 13d is one end of the pressing member 13a. Is inserted into the groove 22 of the part. In other words, one of the two protrusions 21 is disposed between the two protrusions 23, and one of the two protrusions 23 is disposed between the two protrusions 21.

  Although not shown in the figure, two protrusions and grooves are also formed on both end portions of the pressing members 13b and 13c. The protrusion formed at one end of the pressing member 13b is inserted into the groove 22 formed at the other end of the pressing member 13a, and the protrusion 21 formed at the other end of the pressing member 13a is inserted into the pressing member 13b. It is inserted into the opposite groove. A protrusion formed at one end of the pressing member 13c is inserted into a groove formed at the other opposite end of the pressing member 13b, and a protrusion formed at the other end of the pressing member 13b is inserted into the pressing member 13c. It is inserted into the opposite groove. A protrusion formed at the other end of the pressing member 13d is inserted into a groove formed at the opposite end of the pressing member 13c, and the protrusion formed at that end of the pressing member 13d is pressed against the pressing member 13c. Are inserted into the opposite grooves.

  The length of the protrusion formed at the end of each pressing member and the depth of the groove of the protrusion formed at the end of each pressing member in the circumferential direction of the clamp support portion 12 are as follows. As described above, each pressing member is attached to the pipe so that a part of the protruding portion exists in the groove while being pressed against the inner surface of the pipe to be welded. It is set so that the tip of the protruding portion does not contact the bottom surface of the groove while being separated from the inner surface.

  The through holes 17 a, 17 b, 17 c, and 17 d are formed on the outer peripheral portion of the clamp support portion 12, and are arranged every 90 ° in the circumferential direction of the clamp support portion 12. The through holes 17 a, 17 b, 17 c and 17 d penetrate the clamp support portion 12 and extend in the axial direction of the connecting shaft 18. Each through-hole is disposed between two actuators adjacent in the circumferential direction of the clamp support portion 12.

  The ring-shaped expansion / contraction member 20 has a bellows structure that can expand and contract in the radial direction of the clamp support portion 12. The elastic member 20 is disposed so as to surround the outer peripheral surface of the clamp support portion 12, and the inner end portion of the elastic member 20 is attached to the outer peripheral surface of the clamp support portion 12 over the entire circumference. The outer end portion of the elastic member 20 is attached to the inner surface of each of the pressing members 13a, 13b, 13c, and 13d that faces the outer peripheral surface of the clamp support portion 12. The elastic member 20 seals a gap formed between each of the pressing members 13a, 13b, 13c, and 13d and the clamp support portion 12. The expandable member 20 is a seal member that seals between the pressing members 13a, 13b, 13c, and 13d and the clamp support portion 12.

  The clamp device (first clamp device) 2 includes a disk-shaped clamp support portion (first clamp support portion) 3, arc-shaped pressing members (first pressing members) 4a, 4b, 4c, 4d, and actuators 6a, 6b. , 6c, 6d and a ring-shaped elastic member 7. The pressing members (first moving devices) 4b and 4d and the actuators 6b and 6d are not shown. The connecting shaft 18 passes through the through hole 8 formed at the center of the clamp support portion 3. The clamp support 3 is rotatably attached to the connecting shaft 18 by a ball bearing 9 inserted into the through hole 8. The actuators 6a, 6b, 6c, and 6d are provided on the outer peripheral portion of the clamp support portion 3, and are arranged at equal intervals in the circumferential direction of the clamp support portion 3 like the actuators 15a, 15b, 15c, and 15d.

  The pressing members 4a, 4b, 4c, and 4d are arranged opposite to the outer peripheral surface of the clamp support portion 3 in the radial direction of the clamp support portion 3 in the same manner as the press members 13a, 13b, 13c, and 13d. Surrounding. The pressing members 4a, 4b, 4c, and 4d are arranged in the order of the pressing member 4a, the pressing member 4b, the pressing member 4c, and the pressing member 4d in the circumferential direction of the clamp support portion 3. The holding part 5a of the pressing member 4a is connected to the actuator 6a. The holding portion 5c of the pressing member 4c is connected to the actuator 6c. Similarly, the holding portion 5b of the pressing member 6b is connected to the actuator 6b, and the holding portion 5d of the pressing member 4d is connected to the actuator 5d.

  Like the pressing members 13a and 13d, two arc-shaped protrusions extending in the circumferential direction are formed at both ends of the pressing members 4a, 4b, 4c and 4d in the circumferential direction of the clamp support portion 3, respectively. A groove is formed between these protrusions. The width of these protrusions in the radial direction of the clamp support 3 is the same as the width of the pressing member 4 in the radial direction of the clamp support 3. At the end portions of the pressing members 4a, 4b, 4c, and 4d that are adjacent to each other in the circumferential direction of the clamp support portion 3, the protruding portions of the pressing members are respectively inserted into the grooves of the other pressing members adjacent thereto. .

  The ring-shaped expansion / contraction member 7 has a bellows structure that can expand and contract in the radial direction of the clamp support portion 3. The elastic member 7 is disposed so as to surround the outer peripheral surface of the clamp support portion 3, and the inner end portion of the elastic member 7 is attached to the outer peripheral surface of the clamp support portion 3 over the entire circumference. The outer end of the elastic member 7 is attached to the inner surface of each of the pressing members 4a, 4b, 4c, 4d that faces the outer peripheral surface of the clamp support portion 3. The elastic member 7 seals a gap formed between each of the pressing members 4 a, 4 b, 4 c, 4 d and the clamp support portion 3. The elastic member 7 is a seal member that seals between the pressing members 4 a, 4 b, 4 c, 4 d and the clamp support portion 3.

The cylindrical member 10 is disposed so as to surround the coupling shaft 18, and one end portion of the cylindrical member 10 is attached to the side surface of the clamp support portion 3 that faces the clamp support portion 12. The central axis of the cylindrical member 10 coincides with the central axis of the connecting shaft 18. The outer diameter of the cylindrical member 10 is set so that the inner surface of the cylindrical member 10 is located inside the through holes 17a, 17b, 17c, and 17d formed in each of the actuators attached to the clamp support portion 12 and the clamp support portion 12. Is set. A circular groove 16 for inserting the end of the cylindrical member 10 attached to the clamp support 3 is formed on the side of the clamp support 12 facing the clamp support 3. The cylindrical member 10, the clamp support portion 12, may be attached to the side opposite to the clamp support portion 3. In this case, a circular groove 16 into which the distal end portion of the cylindrical member 10 is inserted is formed on the side surface of the clamp support portion 3 that faces the clamp support portion 12.

  Further, a pair of rotation prevention members 34 that are round bars are attached to the side surface of the clamp support portion 3 to which the cylindrical member 10 is attached, and extend toward the clamp support portion 12. A pair of circular through holes 35 are formed at a predetermined interval at positions of the clamp support portion 12 that face the rotation preventing members 34, respectively. The pair of rotation prevention members 34 are inserted into a pair of through holes 35 formed in the clamp support portion 12. A pair of rotation prevention members 34 are attached to the side surfaces of the clamp support portion 12 facing the clamp support portion 3, and a pair of through holes 35 are formed at positions facing the rotation prevention members 34 of the clamp support portion 3. May be.

  The oil supply hose 31 extends toward the clamp support portion 3 through a through hole formed in the clamp support portion 12, and is attached to the side surface of the clamp support portion 3 that faces the clamp support portion 12. An oil supply passage 32 is formed in the clamp support portion 3 and communicates with the actuators 6a, 6b, 6c, and 6d, respectively. The oil supply hose 31 is connected to the oil supply passage 32. The oil supply hose 33 is attached to the side surface of the clamp support portion 12 that does not face the clamp support portion 3. The oil supply hose 33 is connected to an oil supply passage (not shown) formed in the clamp support portion 12 and connected to the actuators 15a, 15b, 15c, and 15d.

  An inert gas supply hose (not shown) is connected to the through holes 17a and 17b, for example, and is attached to the side surface of the clamp support portion 12 that does not face the clamp support portion 3. Inert gas discharge hoses (not shown) are connected to the through holes 17c and 17d, for example, and attached to the side surfaces of the clamp support portion 12 that do not face the clamp support portion 3.

  A pipe welding method according to the first embodiment using the pipe welding support apparatus 1 will be described. In this embodiment, the pipe 25A and the pipe 25B are welded (see FIG. 7).

  Before welding these pipes, the clamp device 2 of the pipe welding support apparatus 1 is inserted into one pipe 25A (see FIG. 4). After the clamp device 2 is inserted into the pipe 25A, oil is supplied to the actuators 6a, 6b, 6c, and 6d through the oil supply hose 31 and the oil supply passage 32. Actuators 6a, 6b, 6c and 6d are actuated by the pressure of the oil to move each of pressing members 4a, 4b, 4c and 4d toward the inner surface of pipe 25A. At this time, the movement amounts of the pressing members 4a, 4b, 4c, and 4d are the same. When the pressing members 4a, 4b, 4c, 4d are pressed against the inner surface of the pipe 25A by the actuators 6a, 6b, 6c, 6d, the supply of oil into the actuators 6a, 6b, 6c, 6d is stopped, and the pressing members The movement toward the inner surface of each pipe 25A of 4a, 4b, 4c, and 4d is stopped. Since each of the pressing members 4a, 4b, 4c, and 4d has the same radius of curvature of the surface that contacts the inner surface of the pipe 25A as the curvature of the inner surface of the pipe 25A, the pressing members 4a, 4b, 4c, and 4d are connected to the pipe 25A. When pressed against the inner surface, the central axis of the pipe 25 </ b> A coincides with the central axis of the connecting shaft 18. When each of the pressing members 4a, 4b, 4c, and 4d moves toward the inner surface of the pipe 25A, the elastic member 7 is stretched in the radial direction of the clamp support portion 3.

  Next, the clamp device 11 of the pipe welding support device 1 disposed in the pipe 25B to be welded with the pipe 25A is fixed to the pipe 25B (see FIG. 5). When the clamp device 11 is fixed to the pipe 25B, the actuator 15a, 15b, 15c, 15d of the clamp device 11 arranged in the pipe 25B is passed through the oil supply hose 33 and the oil supply passage formed in the clamp support portion 12. Supply oil. Actuators 15a, 15b, 15c, and 15d are actuated by the pressure of the oil, and the pressing members 13a, 13b, 13c, and 13d are moved toward the inner surface of the pipe 25B. At this time, the movement amounts of the pressing members 13a, 13b, 13c, and 13d are the same. When the pressing members 13a, 13b, 13c, 13d are pressed against the inner surface of the pipe 25B by the actuators 15a, 15b, 15c, 15d, the supply of oil into the actuators 15a, 15b, 15c, 15d is stopped, and the pressing members The movement toward the inner surface of each pipe 25A of 13a, 13b, 13c, and 13d is stopped. Since each of the pressing members 13a, 13b, 13c, and 13d has the same radius of curvature as the curvature of the inner surface of the pipe 25A, the pressing members 13a, 13b, 13c, and 13d are connected to the pipe 25A. When pressed against the inner surface of the pipe 25B, the central axis of the pipe 25B coincides with the central axis of the connecting shaft 18. As a result, the central axis of the pipe 25B coincides with the central axis of the pipe 25A, and the alignment of the pipe 25A and the pipe 25B is completed. When each of the pressing members 13a, 13b, 13c, and 13d moves toward the inner surface of the pipe 25B, the elastic member 20 is stretched in the radial direction of the clamp support portion 12.

  Thereafter, the interval between the groove of the pipe 25A and the groove of the pipe 25B is adjusted. In order to weld the pipe 25A and the pipe 25B, it is necessary to make the interval between the grooves formed at the end of each pipe a predetermined size. This adjustment of the interval is performed by rotating the connecting shaft 18 by the operator turning the handle 36. The connecting shaft may be driven by driving the motor described above. In a state where the pair of rotation preventing members 34 are inserted into the pair of through holes 35 formed in the clamp support portion 12 and the rotation of the clamp support portion 12 is prevented, the clamp support portion 12 is rotated by the rotation of the connecting shaft 18. Approaching the clamp support portion 3, the interval between the groove of the pipe 25A and the groove of the pipe 25B becomes narrower. When the interval reaches a predetermined size, the rotation of the connecting shaft 18 is stopped. The smaller the pitch of the screw holes of the clamp support portion 12 and the screws 19 of the connecting shaft 18, the more accurately the interval between the grooves can be adjusted.

  When the adjustment of the gap between the grooves is finished, the tip of the cylindrical member 10 is inserted into a circular groove 16 formed on the side surface of the clamp support portion 12. When the depth of the circular groove 16 is shallow, the tip of the cylindrical member 10 hits the bottom surface of the circular groove 16, making it impossible to move the clamp support portion 12 toward the clamp support portion 3, and the interval between the grooves. Cannot be adjusted to a predetermined dimension. In order to prevent this, the circular groove 16 is deepened to some extent. By inserting the tip of the cylindrical member 10 into the circular groove 16, the pressing members 4a, 4b, 4c, 4d, the expansion member 7, the clamp support part 3, the cylindrical member 10, and the clamp support are provided inside the pipes 25A and 25B. An annular space 26 surrounded by the portion 12, the elastic member 20, and the pressing members 13a, 13b, 13c, and 13d is formed. The clamp support portions 3 and 12 are members that form part of the side wall of the annular space 26 and isolate the inside and outside of the annular space 26. The annular space 26 communicates with a region outside the pipes 25A and 25B through a gap between the groove of the pipe 25A and the groove of the pipe 25B. Further, the through holes 17a, 17b, 17c, and 17d are also connected to the annular space 26.

  After the clamping devices 2 and 11 of the pipe welding support device 1 are fixed in the pipes 25A and 25B and the centering of the pipes 25A and 25B and the adjustment of the interval between the grooves are finished, the pipes 25A and 25B are welded. Done. When welding the first pass (first layer) 27 (see FIG. 6), an inert gas (for example, argon gas) is supplied from the inert gas supply hose to the annular space 26 through each of the through holes 17a and 17b. The

  In all the pressing members 4 in a state where the pressing members 4a, 4b, 4c, and 4d are pressed against the inner surface of the pipe 25A, the pressing members adjacent in the circumferential direction of the clamp support portion 3 are at the end of one pressing member. As described above, one formed protrusion exists between the two protrusions formed at the end of the other pressing member, and each protrusion of both pressing members is in the axial direction of the connecting shaft 18. Are overlapping. Moreover, in all the pressing members 13 in a state where the pressing members 13a, 134b, 13c, and 13d are pressed against the inner surface of the pipe 25B, the pressing members adjacent in the circumferential direction of the clamp support portion 12 are one pressing member. As described above, one protrusion formed at the end of the other pressing member exists between the two protrusions formed at the end of the other pressing member, and each protrusion of both pressing members is connected to the connecting shaft. 18 in the axial direction. For this reason, it becomes difficult for the inert gas in the annular space 26 to leak to the outside from between adjacent pressing members. Furthermore, since the expansion members 7 and 20 are attached, the inert gas in the annular space 26 is prevented from leaking from between each pressing member and the clamp support portion to the outside.

  The inert gas supplied to the annular space 26 is discharged out of the annular space 26 through the gaps between the grooves and the through holes 17c and 17d, but the annular space 26 is filled with the inert gas. A welder (not shown) in which welding of the first path 27 of the pipes 25A and 25B is arranged outside the pipes 25A and 25B while supplying an inert gas to the annular space 26 from each of the through holes 17a and 17b. It is done using. This welding may be performed, for example, by attaching a guide rail surrounding the pipe 25A to the outer surface of the pipe 25A and running the welding machine along the guide rail. Welding of the first pass 27 of the pipes 25A and 25B is performed over the entire circumference of the pipe. While the first pass 27 is being welded, the annular space 26 is filled with an inert gas, so that the inner surface of the welded portion of the first pass 27 is not oxidized and high quality welding is realized. it can.

  After the welding of the first pass 27 over the entire circumference of the pipe is completed, the supply of the inert gas to the annular space 26 through the inert gas supply hose and the through holes 17a and 17b is stopped. Each welding from the second pass to the final pass is sequentially performed using a welding machine. In each welding from the second pass to the final pass, the inert gas is not supplied to the annular space 26. Also during the welding from the second pass to the final pass, the pressing members 4a, 4b, 4c, 4d are pressed against the inner surface of the pipe 25A, and the pressing members 13a, 13b, 13c, 13d are also pressed against the inner surface of the pipe 25B. Yes. When the final pass welding is completed, the pipes 25A and 25B are joined by the welded portion 27A (see FIG. 7).

  After the welding of the pipe 25A and the pipe 25B is completed, hydraulic pressure is applied to the actuators 6a, 6b, 6c, and 6d in the opposite directions to move the pressing members 4a, 4b, 4c, and 4d to the connecting shaft 18 side. . As a result, these pressing members are separated from the inner surface of the pipe 25 </ b> A, and the elastic member 7 is contracted in the radial direction of the clamp support portion 3. Further, hydraulic pressure is applied in the opposite directions in the actuators 15a, 15b, 15c, and 15d, and the pressing members 13a, 13b, 13c, and 13d are moved to the connecting shaft 18 side. As a result, these pressing members are separated from the inner surface of the pipe 25 </ b> B, and the expandable member 20 is contracted in the radial direction of the clamp support portion 12.

  By pulling the inert gas supply hose and the inert gas discharge hose (or oil supply hoses 31 and 33), the pipe welding support device 1 is taken out from the pipes 25A and 25B. When welding a long pipe using the pipe welding support device 1 as in a nuclear power plant, as described in JP-A-4-200787, traveling wheels are provided on each of the clamp support portions 3 and 12. For example, the pipe welding support device 1 may be recovered from the pipes 25A and 25B by driving a traveling wheel attached to the clamp support part 12 with a motor attached to the clamp support part 12.

  Thus, the welding work for the pipes 25A and 25B using the pipe welding support apparatus 1 is completed.

  According to the present embodiment, the clamp support part 3 having the pressing members 4a, 4b, 4c and 4d to be inserted, which is detachably fixed in the pipe 25A, and the pressing member which is detachably fixed in the pipe 25B. Since the clamp support part 12 having 13a, 13b, 13c, 13d is attached to the connection shaft 18, and the clamp support part 12 is attached to the connection shaft 18 so as to be movable in the axial direction of the connection shaft 18, The pipes 25A and 25B to be welded can be accurately centered, and the time required for adjusting the gap between the groove formed in the pipe 25A and the groove formed in the pipe 25B can be increased. It can be shortened while holding. Further, the interval can be adjusted with high accuracy.

  In this embodiment, the cylindrical member 10 is attached to the side surface of the clamp support portion 3 that faces the clamp support portion 12, and the distal end portion of the cylindrical member 10 is inserted into the side surface of the clamp support portion 12 that faces the clamp support portion 3. The circular groove 16 is formed, and the tip of the cylindrical member 10 is inserted into the circular groove 16 when adjusting the interval between the groove of the pipe 25A and the groove of the pipe 25B. An annular space 26 can be formed between the pipes 25A and 25B to be welded and the cylindrical member 10 while adjusting the interval. For this reason, the inert gas supplied through the through holes 17a and 17b formed in the clamp support portion 12 can be filled in the annular space 26, and the welded portion of the first path 27 of the pipe 25A and the pipe 25B. It is possible to prevent oxidation of the inner surface.

  In this embodiment, gaps formed between the pressing members 4a, 4b, 4c, and 4d and the clamp support portion 3 are sealed by the expansion and contraction member 7, and the pressing members 13a, 13b, 13c, and 13d are clamped and supported. Since the gap formed between the portions 12 is sealed by the elastic member 20, the amount of the inert gas in the annular space 26 that flows out through the gap to the outside can be remarkably reduced. The amount of gas used can be reduced. Further, the inside of the annular space 26 can be effectively made into an inert gas atmosphere with a small amount of inert gas.

  In the clamp devices 2 and 11, since the protrusions and the grooves are formed at both ends in the circumferential direction of the clamp support portion of each pressing member as described above, the pressing member is respectively radiated by the actuator by the radius of the clamp support portion. When moving in the direction, interference between adjacent pressing members is avoided, and the pressing members can be moved smoothly. Further, when each pressing member is pressed against the inner surface of the pipe, a protrusion formed at the end of one pressing member adjacent in the circumferential direction of the clamp support portion is formed at the end of the other pressing member. Since it overlaps with the protrusion, the amount of the inert gas in the annular space 26 flowing out from between the pressing members adjacent in the circumferential direction of the clamp support portion can be remarkably suppressed.

  In this embodiment, the clamp device 2 is mounted in the pipe 25A, the clamp device 11 is mounted in the pipe 25B, and the pipe 25A and the pipe 25B are welded. Therefore, the welded portion 27A of the pipe 25A and the pipe 25B and this welding are performed. The tensile residual stress in each inner surface of the heat affected zone around the portion 27 is reduced, and the occurrence of stress corrosion cracking in the welded portion 27 and the heat affected zone is suppressed.

  In the present embodiment, since the connecting shaft 18 is rotated to adjust the dimension between the clamp support portion 3 and the clamp support portion 12, the mechanism for adjusting the distance between the grooves of the pipes 25A and 25B is simplified. Therefore, the pipe welding support device 1 can be made compact.

  The inventors confirmed that the tensile residual stress in this example was reduced by simulation using a computer. The results of this simulation will be described below.

  In this simulation, a case in which pipes 25A and 25B made of austenitic stainless steel having an outer diameter of 318.5 mm and a thickness of 21.4 mm are welded without using the pipe welding support device 1 having the clamp devices 2 and 11 and It performed about the case welded using it, and calculated distribution of the residual stress of piping in each case.

  FIG. 8 shows the distribution of residual stress in the axial direction of the pipe 25B corresponding to the distance in the pipe axial direction from the center of the welded portion 27A on the inner surface of the pipe 25B at a certain position in the circumferential direction of the pipe 25B. . FIG. 9 shows the distribution of residual stress in the circumferential direction of the pipe 25B corresponding to the distance in the pipe axis direction from the center of the welded portion 27A on the inner surface of the pipe 25B at a certain position in the circumferential direction of the pipe 25B. .

  8 and 9, the distance of 0 mm is the center position of the welded portion 27A. The residual stress in the pipe axis direction when the clamp devices 2 and 11 are not used becomes a tensile residual stress of 200 MPa at the center of the welded portion 27A as shown by a solid line in FIG. On the other hand, the residual stress in the pipe axis direction when the clamping devices 2 and 11 are used is improved to 5 MPa at the center of the welded portion 27A as shown by the broken line in FIG. The residual stress in the circumferential direction of the pipe at the center of the welded portion 27A is 350 MPa tensile residual stress when the clamp devices 2 and 11 are not used, and 170 MPa tensile residual stress when the clamp devices 2 and 11 are used. To be improved.

  The reason why the tensile residual stress is reduced in the inner surface of the welded portion 27A and the like by fixing the clamp devices 2 and 11 in the pipes 25A and 25B and welding the pipes 25A and 25B is as follows. When the pipes 25A and 25B are welded without fixing the clamp devices 2 and 11 in the pipes 25A and 25B, the welding causes deformation such that the pipes 25A and 25B are pulled toward the welded portion 27A. For this reason, the tensile residual stress in the inner surface of the welded portion 27A increases. On the other hand, when the clamping devices 2 and 11 are fixed in the pipes 25A and 25B as in the present embodiment, the pressing members 4a to 4d are pressed against the inner surface of the pipe 25A so that the pressing members 13a to 13d Since it is pressed against the inner surface of the pipe 25B, deformation by which the pipes 25A and 25B are pulled toward the welded portion 27A by welding is suppressed by the pressed pressing members 4a to 4d and the pressing members 13a to 13d. For this reason, in this embodiment, the tensile residual stress on the inner surface of the welded portion 27A is reduced.

  In a welded part of a pipe made of austenitic stainless steel, stress corrosion cracking occurs when water with a large amount of dissolved oxygen flows in the pipe. However, since the tensile residual stress is reduced in the welded portion 27A welded using the pipe welding support device 1 having the clamp devices 2 and 11, the occurrence of stress corrosion cracking in the welded portion 27A is suppressed.

  In butt welding of pipes, a ring-shaped molten material called an insert ring may be used between the grooves during the first pass welding. In the case of using an insert ring, it is only necessary to start welding of the pipe as follows. One clamp device (for example, the clamp device 2) in which each pressing member is moved to the clamp support portion side is ring-shaped. The clamp device 2 is inserted into the pipe 25A and the clamp device 11 is inserted into the pipe 25B with the insert ring placed on the connecting shaft 18. Then, each pressing member of each clamping device is pressed against the inner surface of the corresponding pipe, and in a state where the insert ring is aligned with the groove of the pipe, the connecting shaft 18 is rotated to bring the clamping device 11 closer to the clamping device 2 and insert A ring is pinched | interposed with each groove | channel of piping 25A, 25B, and welding of these piping is started after that. The thickness of the insert ring corresponds to the distance between the grooves. In order to easily place the insert ring between the grooves of the pipes 25A and 25B, a grip portion is attached to the outer periphery of the insert ring, and an operator holds the grip portion when adjusting the interval between the grooves. The insert ring should be positioned between the grooves. The grip portion of the insert ring is removed after the insert ring is sandwiched between the grooves.

  A pipe welding method according to embodiment 2, which is another preferred embodiment of the present invention, will be described below.

  Also in the pipe welding method of the present embodiment, the above-described pipe welding support apparatus 1 is used. As in the first embodiment, the clamp device 2 of the pipe welding support device 1 is inserted into the pipe 25A and the pressing members 4a, 4b, 4c, and 4d are pressed against the inner surface of the pipe 25A to fix the clamp apparatus 2 in the pipe 25A. To do. The pressing members 13a, 13b, 13c, and 13d of the clamp device 11 of the pipe welding support device 1 disposed in the pipe 25B to be welded to the pipe 25A are pressed against the inner surface of the pipe 25B to fix the clamp device 11 in the pipe 25B. To do. The connecting shaft 18 is rotated to bring the clamping device 11 closer to the clamping device 2 and adjust the interval between the grooves of the pipes 25A and 25B. The first pass 27 of the pipes 25A and 25B is welded while supplying an inert gas to the annular space 26 as in the first embodiment. After the welding of the first pass 27 is completed over the entire circumference of the pipe, the supply of the inert gas to the annular space 26 is stopped.

  Thereafter, welding from the second pass to the final pass for connecting the pipes 25A and 25B is performed outside the first pass. When performing welding from the second pass to the final pass, open the on-off valve provided in the water supply hose connected to the inert gas supply hose, and upstream from the connection point of the inert gas supply hose and the water supply hose. Close the open / close valve provided on the inert gas supply hose and open the open / close valve provided on the water discharge hose connected to the inert gas discharge hose, downstream of the connection point between the inert gas discharge hose and the water discharge hose. Close the on-off valve on the inert gas discharge hose. Therefore, the water (cooling medium) is connected to the water supply hose, the inert gas supply hose and the through holes 17a and 17b through the first path 27, the pipes 25A and 25B, the pressing members 4a, 4b, 4c and 4d, and the expansion and contraction. It is supplied into an annular space 26 surrounded by the member 7, the clamp support portion 3, the cylindrical member 10, the clamp support portion 12, the telescopic member 20, and the pressing members 13 a, 13 b, 13 c and 13 d. This water is discharged from the annular space 26 through the through holes 17c and 17d, the inert gas discharge hose and the water discharge hose. Thus, in this embodiment, welding from the second pass to the final pass is performed while water is supplied to the annular space 26. That is, the welding is performed while the inner surface of the first pass 27 is cooled with water, and the temperature of the inner surface of the first pass 27 to be cooled is the portion where the welding from the second pass to the final pass is performed. It becomes lower than the temperature. For this reason, after welding of the pipe 25A and the pipe 25B is finished, compressive residual stress is applied to the inner surfaces of the welded portion 27A and the heat affected zone. After the welding of the pipe 25A and the pipe 25B is finished, the supply of water from the through holes 17a and 17b to the annular space 26 is stopped. And the piping welding assistance apparatus 1 is taken out from the welded piping 25A and 25B.

  In the present embodiment, each effect produced in the first embodiment can be obtained. Furthermore, in this embodiment, after the welding of the first pass 27 is completed, water can be supplied into the annular space 26 formed by the pipe welding support device 1 through the through holes 17a and 17b. Since the welding from the second pass to the final pass is performed outside the first pass 27 while cooling, the residual stress at the welded portion 27A of the pipe 25A and the pipe 25B and the inner surface of the heat affected zone is improved as compared with the first embodiment. be able to. That is, in this embodiment, compressive residual stress can be applied to the inner surface.

  When welding austenitic stainless steel pipes 25A and 25B having an outer diameter of 318.5 mm and a thickness of 21.4 mm using the pipe welding support apparatus 1 having the clamp devices 2 and 11, water cooling is performed during welding. A simulation using a computer was performed for the case where the tensile stress was not performed and the case where the water was cooled, and the effect of reducing the residual tensile stress was confirmed.

  FIG. 10 shows the distribution of residual stress in the axial direction on the inner surface of the pipe when water cooling is performed and when it is not performed. The distribution of the residual stress in the axial direction is the residual stress in the axial direction of the pipe 25B corresponding to the distance in the pipe axial direction from the center of the welded portion 27A on the inner surface of the pipe 25B at a certain position in the circumferential direction of the pipe 25B. Distribution. FIG. 11 shows the distribution of the residual stress in the circumferential direction on the inner surface of the pipe when water cooling is performed and when it is not performed. The distribution of the residual stress in the circumferential direction is such that the residual stress in the circumferential direction of the pipe 25B corresponding to the distance in the pipe axial direction from the center of the welded portion 27A on the inner surface of the pipe 25B at a certain position in the circumferential direction of the pipe 25B. Distribution.

  In Example 1 in which the pipes 25A and 25B were welded without water cooling of the first pass 27 using the pipe welding support device 1, the tensile residual stress in the axial direction of the inner surface at the center of the welded portion 27A was 5 MPa. On the other hand, in the present embodiment in which the pipe 25A and 25B are welded by performing the water cooling of the first pass 27 using the pipe welding support device 1, the residual stress in the axial direction of the inner surface at the center of the weld 27A. Is improved to a compressive residual stress of 250 MPa. Further, the residual stress in the circumferential direction of the inner surface at the center of the welded portion 27A in the first embodiment is a tensile residual stress of 170 MPa, whereas the residual stress in the circumferential direction of the inner surface at the center of the welded portion 27A in the present embodiment. Is improved to a compressive residual stress of 360 MPa. It is known that stress corrosion cracks do not occur under compressive residual stress. By performing the pipe welding method of this embodiment, the occurrence of stress corrosion cracks in the welded portions 27A and heat-affected portions of the pipes 25A and 25B is prevented. Can be prevented.

  A pipe welding method according to embodiment 3, which is another preferred embodiment of the present invention, will be described with reference to FIG.

  In the present embodiment, similarly to the first embodiment, welding from the first pass 27 to the final pass is performed on the pipes 25 </ b> A and 25 </ b> B using the pipe welding support device 1. After the welding to the pipes 25A and 25B is completed and the pipe 25A and the pipe 25B are joined by the welded portion 27A, the actuators 6a, 6b, 6c, and 6d and the actuators 15a, 15b, 15c, and 15d are operated. The pressing members 4a, 4b, 4c, and 4d are further pressed toward the inner surface of the pipe 25A, and the pressing members 13a, 13b, 13c, and 13d are further pressed toward the inner surface of the pipe 25B, and the pipes 25A and 25B are respectively pressed. Is expanded outward by 0.03 mm. After expanding each of the pipes 25A and 25B, the pipe welding support apparatus 1 is taken out from the welded pipes 25A and 25B.

  The present embodiment can obtain each effect obtained in the first embodiment. Furthermore, in this embodiment, since the pipes 25A and 25B are welded and then expanded using the pipe welding support apparatus 1, the welded portion 27A of the pipe 25A and the pipe 25B and the inner surface of the heat affected zone remain more than in the first embodiment. The stress can be improved as compared with Example 1. That is, in this embodiment, compressive residual stress can be applied to the inner surface.

  When the austenitic stainless steel pipes 25A and 25B having an outer diameter of 318.5 mm and a thickness of 21.4 mm are butt welded using the pipe welding support apparatus 1 having the clamp devices 2 and 11, the pipes are welded. A simulation using a computer was performed on the case where 25A and 25B were not expanded and the case where the tube was expanded, and the effect of reducing the tensile residual stress was confirmed. In the expanded case, the case where the pipes 25A and 25B were expanded by 0.03 mm each was targeted.

  FIG. 13 shows the distribution of the residual stress in the axial direction on the inner surface of the pipe in the case where the pipe is not expanded. The distribution of the residual stress in the axial direction is the residual stress in the axial direction of the pipe 25B corresponding to the distance in the pipe axial direction from the center of the welded portion 27A on the inner surface of the pipe 25B at a certain position in the circumferential direction of the pipe 25B. Distribution. FIG. 14 shows the distribution of residual stress in the circumferential direction on the inner surface of the pipe in the case where the above-mentioned pipe expansion is performed. The distribution of the residual stress in the circumferential direction is such that the residual stress in the circumferential direction of the pipe 25B corresponding to the distance in the pipe axial direction from the center of the welded portion 27A on the inner surface of the pipe 25B at a certain position in the circumferential direction of the pipe 25B. Distribution.

  In Example 1 where the pipes 25A and 25B are welded using the pipe welding support device 1 and the pipes 25A and 25B are not expanded, the tensile residual stress in the axial direction of the inner surface at the center of the welded portion 27A is 5 MPa. On the other hand, in the present embodiment in which the pipes 25A and 25B welded using the pipe welding support apparatus 1 are expanded, the residual stress in the axial direction of the inner surface at the center of the welded portion 27A is 10 MPa. Improved to residual stress. Further, the residual stress in the circumferential direction of the inner surface at the center of the welded portion 27A in the first embodiment is a tensile residual stress of 170 MPa, whereas the residual stress in the circumferential direction of the inner surface at the center of the welded portion 27A in the present embodiment. Is improved to a tensile residual stress of 150 MPa.

  A pipe welding method according to embodiment 4, which is another preferred embodiment of the present invention, will be described with reference to FIG.

  The pipe welding method of the first embodiment is intended for welding pipes, but the pipe welding method of this embodiment is applied when the pipe 28 is welded to the nozzle 29.

  The clamping device 2 of the pipe welding support device 1 is inserted into the nozzle 29 and the pressing members 4 a, 4 b, 4 c, 4 d are pressed against the inner surface of the nozzle 29 to fix the clamping device 2 in the nozzle 29. The pressing members 13a, 13b, 13c, and 13d of the clamp device 11 of the pipe welding support device 1 disposed in the pipe 28 to be welded to the nozzle 29 are pressed against the inner surface of the pipe 28 to place the clamp device 11 in the pipe 25B. Fix it. The connecting shaft 18 is rotated to bring the clamp device 11 closer to the clamp device 2 and adjust the distance between the nozzle 29 and the groove of the pipe 28. Thereafter, the nozzle 29 and the pipe 28 are welded as in the first embodiment. After this welding, the pipe welding support device 1 is taken out from the nozzle 29 and the pipe 28.

  In the present embodiment, each effect produced in the first embodiment can be obtained.

  DESCRIPTION OF SYMBOLS 1 ... Pipe welding assistance apparatus, 2, 11 ... Clamp apparatus, 3, 12 ... Clamp support part, 4a, 4c, 13a-13d ... Pressing member, 6a, 6c, 15a-15d ... Actuator, 7, 20 ... Expansion / contraction member, DESCRIPTION OF SYMBOLS 9 ... Ball bearing, 10 ... Cylindrical member, 16 ... Circular groove, 17a-17d ... Through-hole, 18 ... Connection shaft 21, 23 ... Projection part, 22, 24 ... Groove, 25A, 25B ... Pipe, 26 ... Annular space 27 ... first pass, 27A ... welded part.

Claims (3)

A connecting rod;
A first clamp support portion attached to the connecting rod, a plurality of first pressing members that surround the first clamp support portion and are arranged in the circumferential direction of the first clamp support portion, and the first pressing member are separately provided. A first clamp device having a first moving device attached to the first clamp support portion and moving the first pressing member in a radial direction of the first clamp support portion;
A second clamp support portion attached to the connection rod so as to be movable in the axial direction of the connection rod, and a plurality of second pressing members disposed around the second clamp support portion and arranged in the circumferential direction of the second clamp support portion A second moving device that is separately attached to the member and the second pressing member and is provided on the second clamp support portion, and moves the second pressing member in the radial direction of the second clamp support portion. A clamping device,
A cylindrical member surrounding the connecting rod is attached to one of the side surfaces of the first clamp support part and the second clamp support part that face each other,
A groove having a longitudinal cross-sectional shape of the cylindrical member into which the distal end portion of the cylindrical member is inserted is attached to the cylindrical member of the first clamp support portion and the second clamp support portion. Formed on the side of the clamp support that faces the tip of the tubular member,
An annular first elastic member that expands and contracts in the radial direction of the first clamp support part includes an inner end part attached to the first clamp support part and an outer end part attached to each first pressing member. Have
An annular second expansion / contraction member extending and contracting in the radial direction of the second clamp support portion includes an inner end portion attached to the second clamp support portion and an outer end portion attached to each of the second pressing members. Have
A plurality of through holes are formed in the second clamp support portion outside the cylindrical member;
All the first pressing members respectively form first projecting portions projecting in the circumferential direction at both ends in the circumferential direction of the first clamp support portion, and are adjacent in the circumferential direction of the first clamp support portion. The first pressing members formed on one of the first pressing members and the first protruding portion formed on the other first pressing member of the first pressing members are Overlap in the axial direction, and
All the second pressing members respectively form second projecting portions projecting in the circumferential direction at both circumferential ends of the second clamp support portion, and are adjacent in the circumferential direction of the second clamp support portion. In the second pressing members, the second protruding portion formed on one of the second pressing members and the second protruding portion formed on the other second pressing member are connected to the connecting rod. Overlapping in the axial direction
Using a pipe welding support device,
Inserting the first clamping device into the first pipe;
Pressing the first pressing member against the inner surface of the first pipe by the first moving device to fix the first clamping device in the first pipe;
Inserting the second clamping device into a second pipe to be welded to the first pipe;
Pressing each second pressing member against the inner surface of the second pipe by each second moving device to fix the second clamping device in the second pipe;
The second clamp support portion is moved along the connecting rod toward the first clamp device, and a groove formed in the first pipe and an opening formed in the second pipe facing the groove. Adjust the distance between the ends,
After adjusting the gap interval, the first space between the first clamp device and the second clamp device and in the annular space formed between the tubular member, the first pipe, and the second pipe, 2 supplying an inert gas through the through hole formed in the clamp support part;
While supplying the inert gas to the annular space, welding the first pass to join the first pipe and the second pipe,
The performed after welding of the first pass, the first pipe and the rest of the welding of the second pipe, pipe welding method which comprises carrying out while supplying a cooling medium to the annular space through the through hole. Wherein said second clamp support portion moving to the first clamping device side, pipe welding method according to claim 1 for the connecting rod meshing with the second clamp support portion and the screw is rotated. As a piping support device, the connecting rod is rotatably attached to the first clamp support portion, the second clamp support portion is attached to the connecting rod by meshing with a screw formed on the surface of the connecting rod, The pipe welding method according to claim 1 or 2 , wherein the pipe support device has a configuration in which rotation of the two clamp support parts is constrained by the first clamp support part by a rotation preventing member.

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