JP2015139787A - Pipe welding apparatus, pipe welding system, and pipe welding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pipe welding technique capable of improving the quality of the inner surface of welded portions in which a base pipe is welded to a branch pipe.SOLUTION: A pipe welding apparatus 10 comprises: a first stage 21 moving an interior of a base pipe (first pipe 11) having an opening 13 formed in a side surface thereof, in a longitudinal direction (Z-direction); and an execution unit 30 executing welding along the circumference of a groove portion 14 of a branch pipe (second pipe 12) mounted on the first stage 21 and attached to the opening 13 in a state of contacting the groove portion 14 with the opening 13.

Description

  Embodiments described herein relate generally to piping welding technology.

Like a heat recovery steam generator (HRSG), a structure in which a plurality of branch pipes (second pipes) extend in the vertical direction at regular intervals from the side surface of the main pipe (first pipe) Manual welding such as TIG welding or MAG welding is generally used for joining to the branch pipe.
On the other hand, in order to improve work efficiency and welding quality, a method for automatically welding the mother pipe and the branch pipe by automatic MAG has been developed.

JP 7-214320 A

In the past, since the joining between the mother pipe and the branch pipe is welded from the outside, it is impossible to confirm whether the melt has sufficiently penetrated to the inside of the contacting part.
In the case of welding from the outside, if the melt is sufficiently penetrated to the inside in order to ensure the strength, the inner surface is wavy, and there is a problem that it is difficult to control the properties of the inner surface.
When the properties of the inner surface of the welded portion are unstable, in the boiler, pressure loss occurs when a fluid such as steam passes through the inner surface of the pipe, and there is a concern about performance degradation.

  In welding from the outside, when multiple branch pipes with a small outer diameter and wall thickness are joined to the main pipe at regular intervals, such as a boiler structure, interference between the branch pipe and the welding device occurs during welding work. There is also a problem that man-hours increase in order to avoid this interference.

  The embodiment of the present invention has been made in view of such circumstances, and an object of the present invention is to provide a pipe welding technique for improving the quality of the inner surface of the joint portion of the mother pipe and the branch pipe.

  An embodiment of the present invention is a pipe welding apparatus in which a first stage that moves in the longitudinal direction inside a first pipe that is provided with an opening on a side surface is mounted on the first stage while being mounted on the first stage. And a construction portion for performing welding along the periphery of the groove portion in a state where the groove portion of the second pipe is in contact with the opening.

  The embodiment of the present invention provides a pipe welding technique for improving the quality of the inner surface of the joint portion of the mother pipe and the branch pipe.

The external view which shows the pipe welding apparatus which concerns on embodiment of this invention in the cross section containing the central axis of a main pipe and the central axis of a branch pipe. The external view which shows the pipe welding apparatus which concerns on embodiment of this invention in the orthogonal cross section of the central axis of a mother pipe. Sectional drawing which shows the state which has arrange | positioned the insert ring in the joining position of a mother pipe and a branch pipe.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
As shown in FIGS. 1 and 2, the pipe welding apparatus 10 includes a first stage 21 that moves in the longitudinal direction (Z direction) inside a mother pipe (first pipe 11) having an opening 13 on a side surface. The welding is performed along the periphery of the groove portion 14 with the groove portion 14 of the branch pipe (second pipe 12) mounted on the first stage 21 and attached to the opening 13 in contact with the opening 13. And a construction section 30 to be constructed.

  The construction unit 30 reflects the laser light 40 a irradiated along the Z direction in the longitudinal direction (X direction) of the second pipe 12 and the second pipe 12 from the inside of the first pipe 11. The laser beam 40b is configured to be irradiated obliquely with respect to the major axis direction, and the laser beam 40b is scanned along the periphery of the groove portion 14 by a rotation operation with the major axis direction of the second pipe 12 as the rotation axis. A rotation scanning unit 34.

The rotation scanning unit 34 includes a support 35 that rotates coaxially with the first reflected light 41 by the first reflecting plate 31.
The support 35 reflects the first reflected light 41 further in the rotational radius direction, and reflects the second reflected light 42 by the second reflecting plate 32 toward the periphery of the groove portion 14. And a third reflector 33.
The laser beam 40 b reflected by the second reflecting plate 32 passes through the transmission window 36 and is irradiated on the periphery of the groove portion 14.

Since the space including the optical paths of the first reflected light 41 and the second reflected light 42 is blocked from the space including the peripheral edge of the groove portion 14 by the support 35, the first reflecting plate 31 and the second reflecting plate 32. In addition, the optical component including the third reflector 33 is not contaminated by spatters generated during construction.
Air supplied from an air supply unit (not shown) is blown to the outer surface of the transmission window 36 in the vicinity thereof, and contamination is prevented by blowing off spatter.
Further, the peripheral edge of the groove portion 14 irradiated with the laser beam 40b is purged with an inert gas supplied from a cylinder or the like (not shown) in order to prevent oxidation of the molten metal.

The other optical system (not shown) is fixed to the housing 38 to which the first reflecting plate 31 is fixed, and a hole is provided in the optical path through which the laser light 40a and the first reflected light 41 pass.
The housing 38 and the support 35 are connected by a rolling element 37, and the support 35 is rotationally driven by a motor (not shown) fixed to the housing 38 side.

The first stage 21 is attached to the base 24 (FIG. 2) installed on the inner peripheral surface of the mother pipe (first pipe 11) in a state where movement is restricted only in the longitudinal direction (Z direction). Yes.
A rail 25 a is fixed to the base 24 along the longitudinal direction (Z direction) of the first pipe 11, and a guide 26 a that moves along the rail 25 a is fixed to the first stage 21.
The first stage 21 is driven by a linear motion mechanism (not shown) such as a rack and pinion or a screw shaft.

The second stage 22 is attached to the first stage 21 in a state in which movement is restricted only in the longitudinal direction (X direction) of the second pipe 12.
The second stage 22 is fixed with a guide 26b that moves along a rail 25b fixed to the first stage 21, and is driven by a linear motion mechanism (not shown) such as a rack and pinion or a screw shaft.
Thereby, the 2nd stage 22 can move the construction part 30 along the longitudinal direction (X direction) of the 2nd piping 12. FIG.
And the 2nd stage 22 has the upright surface 27 orthogonal to the moving direction (X direction).

The third stage 23 is attached to the upright surface 27 of the second stage 22 in a state where movement is restricted only in the radial direction (Y direction) of the first pipe 11.
The third stage 23 is fixed with a guide 26c that moves along a rail 25c fixed to the second stage 22, and is driven by a linear motion mechanism (not shown) such as a rack and pinion or a screw shaft.
Further, as described above, the housing 38 to which the first reflector 31 and other optical systems (not shown) are fixed is fixed to the third stage 23.
Thereby, the third stage 23 moves the construction part 30 along the orthogonal direction (Y direction) with respect to both the longitudinal direction (Z direction) of the first pipe 11 and the longitudinal direction (X direction) of the second pipe 12. Can be moved.

By moving the first stage 21 straight in the longitudinal direction (Z direction) of the mother pipe (first pipe 11), welding of the plurality of branch pipes (second pipe 12) can be continuously performed.
By moving and adjusting the first stage 21, the second stage 22, and the third stage 23, the irradiation locus of the laser light 40 b can be combined with the periphery of the groove portion 14.

The movement of the first stage 21, the second stage 22, and the third stage 23 is executed by computer control based on the branch pipe position information input in advance.
Note that at least one of the second stage 22 and the third stage 23 can be omitted if the construction portion 30 can be fixed so that the irradiation locus of the laser beam 40b matches the periphery of the groove portion 14.

  The imaging unit 50 is arranged in the optical path of the laser beam 40a, and branches the reflected light that returns from the periphery of the groove portion 14 in the order of the third reflecting plate 33, the second reflecting plate 32, and the first reflecting plate 31. A half mirror 51, a second half mirror 52 arranged in the optical path of the branched light by the first half mirror 51, and a mirror 53 arranged in the optical path of the transmitted light of the second half mirror 52 are provided.

The reflected light from the second half mirror 52 enters the first camera 56 focused on the periphery of the groove portion 14.
After moving the stages 21, 22, and 23 based on the branch pipe position information, the laser beam 40b is irradiated by irradiating the laser beam 40b at a level that does not melt the metal while rotating the rotary scanning unit 34. The position can be confirmed on the monitor.

And if this irradiation position and the peripheral position of the groove part 14 have shifted | deviated, the movement of each stage 21,22,23 will be finely adjusted and this shift | offset | difference will be eliminated.
Next, the intensity of the laser beam 40b is increased to a level at which the metal is melted, and irradiation is performed, and the welding state of the periphery of the groove portion 14 can be imaged and confirmed on the monitor.
In addition, after the end of welding, the rotary scanning unit 34 is rotated, and the weld bead is observed by the first camera 56, so that the presence or absence of a defect on the weld bead surface can be confirmed.

The reflected light from the mirror 53 enters the second camera 57 focused on the transmission window 36.
Thereby, the contamination state of the outer surface of the transmission window 36 due to the scattered matter accompanying the sputtering during the welding process can be confirmed on the monitor.

In the imaging unit 50, the first half mirror 51, the second half mirror 52, the mirror 53, the first camera 56, the second camera 57, and other optical systems (not shown) are precisely assembled and adjusted and stored in the casing. ing.
The imaging unit 50 is fixed to the same stage (the third stage 23 in the figure) as the housing 38 that houses the first reflector 31 and other optical systems (not shown).

  In FIG. 1, the first half mirror 51, the second half mirror 52, and the mirror 53 are stacked in the longitudinal direction (X direction) of the second pipe 12, but the longitudinal direction (Z direction) of the first pipe 11. ) And the longitudinal direction (X direction) of the second pipe 12 may be laminated in a direction perpendicular to the direction (Y direction).

The proximal end of the optical cable 17 is connected to a laser oscillator (not shown) arranged outside the first pipe 11, and the distal end is connected to the imaging unit 50.
The laser light oscillated by the laser oscillator is transmitted through the optical cable 17 and irradiated from the tip to the internal space of the first pipe 11.

Next, examples of the welding method will be described.
As shown in FIG. 3, an insert ring 18 that melts by laser heating can be inserted and welded to the joint between the mother pipe (first pipe 11) and the branch pipe (second pipe 12).
And this insert ring 18 may make the thickness of the outer side thicker than the inner side of the mother pipe (first pipe 11).

In addition, a wire supply unit (not shown) that supplies a filler wire to the irradiation position of the laser beam 40 b at the periphery of the groove portion 14 can be provided in the rotary scanning unit 34.
The supply section (not shown) has a sheath-type guide (not shown) whose opening tip is scanned along the peripheral edge of the groove portion 14 irradiated with the laser beam 40b, and the filler wire is a mother pipe (first illustration). It is supplied from the outside of one pipe 11) via the inside of this guide.
Further, it is desirable that the supply unit includes a preheating unit for preheating the filler wire.

Moreover, the width of the weld line can be increased by performing welding while the second stage 22 is being oscillated in the longitudinal direction (X direction) of the second pipe 12.
It is desirable that the width of the weld line formed by this swing is wide on the side of the mother pipe 11.
Further, by adjusting the amplitude and frequency of the second stage 22 to be oscillated, the width and surface properties of the weld line can be adjusted.

In addition, after through welding the mother pipe (first pipe 11) and the branch pipe (second pipe 12) in the first step, a filler wire is supplied in the second step to adjust the bead height of the weld line. it can.
Further, in the third step, the bead shape of the weld line can be shaped only by laser irradiation without supplying the filler wire.

According to the pipe welding apparatus of the above-described embodiment, when joining the groove of the second pipe to the side face of the first pipe, welding is automatically performed from the inside of the first pipe, thereby improving work efficiency and joining. The quality of the inner surface of the part can be improved.
Furthermore, since the welding construction part does not need to be inserted inside the branch pipe, the operation can be simplified. For this reason, it becomes easy to weld the continuous branch pipe continuously.

In addition, the structure in which the laser is obliquely irradiated from the inside of the mother pipe during welding is superior to the structure in which the laser head itself is arranged inside the branch pipe, and the construction is performed in a short time. It is possible.
In particular, when a large number of branch pipes are welded to the mother pipe as in HRSG, it is particularly effective that the construction is shortened by the configuration of the present embodiment.
The apparatus can be downsized and can be applied to a mother pipe having a small inner diameter.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, changes, and combinations can be made without departing from the scope of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

  For example, although it demonstrated as what combined optical components, such as the 1st reflective plate 31 and the 1st half mirror 51, it is not necessary to limit to these combinations and if it is the structure which exhibits a predetermined function as an optical transmission means. Good. Further, a lens for collimating the laser emitted from the optical cable 17 and a lens for condensing the laser for irradiating the welding site are not shown, but they are appropriately installed as necessary.

  Further, TIG welding or MIG welding is possible if the tip of the electrode is made to approach the site to be welded and rotated around the rotation axis along the X direction. However, in the case of laser welding, it is not necessary to bring the electrode tips close to each other, so that the positioning is superior, and it is excellent in that the configuration of the pipe welding apparatus can be simplified in comparison.

  Further, when a plurality of branch pipes 12 are provided in the circumferential direction of the mother pipe 11, an axis for moving the pipe welding apparatus 10 along the circumferential direction of the mother pipe 11 may be added. A drive device that relatively moves the base 24 from the outside of the mother pipe 11 in the circumferential direction of the mother pipe 11 may be provided, or between the base 24 and the first stage 21 along the circumferential direction of the mother pipe 11. An arcuate stage may be added to be movable.

  DESCRIPTION OF SYMBOLS 10 ... Pipe welding apparatus, 11 ... 1st piping, 12 ... 2nd piping, 13 ... Opening, 14 ... Groove part, 17 ... Optical cable, 18 ... Insert ring, 21 ... 1st stage, 22 ... 2nd stage, 23 ... 3rd stage, 24 ... Base, 25 (25a, 25b, 25c) ... Rail, 26 (26a, 26b, 26c) ... Guide, 27 ... Upright surface, 30 ... Construction part, 31 ... First reflector, 32 2nd reflector, 33 ... 3rd reflector, 34 ... rotating scanning part, 35 ... support, 36 ... transmission window, 37 ... rolling element, 38 ... housing, 40 (40a, 40b) ... laser beam, 41 ... 1st reflected light, 42 ... 2nd reflected light, 50 ... Image pick-up part, 51 ... 1st half mirror, 52 ... 2nd half mirror, 53 ... Mirror, 56 ... 1st camera, 57 ... 2nd camera.

Claims (6)

A first stage that moves in the longitudinal direction inside a first pipe having an opening on a side surface;
A construction portion that is mounted on the first stage and that welds along the periphery of the groove portion in a state where the groove portion of the second pipe attached to the opening is in contact with the opening. A pipe welding apparatus comprising: In the pipe welding apparatus according to claim 1,
The construction portion is configured to irradiate laser light obliquely with respect to the major axis direction of the second pipe from the inside of the first pipe, and the major axis direction of the second pipe is a rotation axis. A pipe welding apparatus, comprising: a rotation scanning unit that scans the laser beam along a peripheral edge of the groove portion by a rotation operation. In the pipe welding apparatus according to claim 1 or 2,
The said welding part is mounted in the said 1st stage through the 2nd stage which moves along the longitudinal direction of the said 2nd piping, The pipe welding apparatus characterized by the above-mentioned. In the piping welding apparatus according to any one of claims 1 to 3,
The construction section is mounted on the first stage via a third stage that moves along a direction orthogonal to both the longitudinal direction of the first pipe and the longitudinal direction of the second pipe. Pipe welding equipment. The pipe welding apparatus according to any one of claims 2 to 4,
A control device for controlling the driving of the pipe welding device,
The controller is
Laser oscillator control means, image processing means of branch pipe position measuring device provided in the pipe welding apparatus, image processing means of groove position measuring apparatus and movement control means of pipe welding apparatus, branch pipe position and laser irradiation condition in advance Storage means for storing movement speed, peristaltic width, and filler wire supply amount,
The pipe welding apparatus further includes an imaging unit that branches and images reflected light from the periphery of the groove portion in the optical path of the laser light,
The controller is
Detecting the actual position of the second pipe from the image captured by the imaging unit;
Based on the detection result, the position of the pipe welding apparatus is corrected,
Further, the actual groove position is detected by the imaging means,
While correcting the laser beam irradiation position based on this detection result,
One or more groove gaps are measured and corrected so that the peristaltic width and filler wire supply amount stored in advance according to the groove gap can be supplied according to the groove gap. . Moving the first stage in the longitudinal direction inside the first pipe having an opening on the side surface;
In the state where the groove portion of the second pipe attached to the opening is in contact with the opening, the step of performing welding along the periphery of the groove portion by the construction portion mounted on the first stage; A pipe welding method comprising:

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