JPH0857667A - Seam profiling control method for beam welded pipe and seam profiling controller - Google Patents

Abstract

PURPOSE: To provide a seam profiling control method for a welded pipe without generating weld defects and a seam profiling controller. CONSTITUTION: A processing head 5 turnable around the axis x-x of the pipe is arranged above an open pipe H and the seam deviation of a butt part 6 is detected by a seam deviation detecting section 20. An arithmetic section 31 calculates the rotating quantity of a processing head 5 and the rotating quantity of mirrors 1, 2 according to the result of the detection and a processing head control section 30 turns the processing head 5. Mirror control sections 32, 33 turn the mirrors 1, 2. The butt part 6 of the open pipe H is irradiated with a laser beam 9 from a direction existing on a plane inclusive of the central line x-x of the mill from the processing head 5, by which the beam welded pipe is produced without generating the weld defects in the butt end faces.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seam copying control method for seam welding a metal pipe by beam welding and an apparatus used for the same.

[0002]

2. Description of the Related Art In energy beam welding, the energy of a heat source is higher than that of other welding methods, so that the penetration into the welded pipe is deep and high-speed welding is possible. Moreover, since the total heat input is smaller than that of other welding methods, the condition of the welded portion is improved. In order to further increase the welding speed, a method of performing fusion welding using a laser beam after heating with high frequency, a composite heat source welding method, and the like have been proposed in JP-A-2-70379.

By the way, the energy beam welding method is MI
The welding bead width is narrower than that of general fusion welding methods such as G and TIG. In the composite heat source welding method as described above, it is possible to make the shape of the weld bead slightly wider than in the case of using the laser beam alone, but the bead width is extremely narrow as compared with the general fusion welding method. For this reason, welding defects such as seam deviation are likely to occur.

Further, when welding a plate-shaped object to be welded, it suffices to pay attention only to the parallel deviation from the reference line.
In tubular welding, it is necessary to consider the twist of the pipe,
It is not possible to prevent seam shift only by detecting one point on the weld end surface. To resolve this issue,
In Japanese Patent No. 31799, two end faces of the welded pipe are detected on the upstream side of welding, the displacement amount of the abutting portion from the welding reference line is calculated based on each position vector, and the machining head is moved accordingly. A seam copying control method has been proposed.

[0005]

An apparatus used in such a conventional seam copying control method is provided with a working head for propagating a laser beam and irradiating the abutting portion of a welded pipe with the working head. It is designed to follow the gap and move. FIG. 10 is a side view showing the configuration of a processing head of a conventional laser welding device. In the figure, H is an open pipe, and the metal strip is conveyed horizontally by various roll forming stands (not shown) arranged in tandem in the longitudinal direction, and the cross section is circular so that the widthwise end faces of the metal strip face each other. It is composed.

The processing head 15 for propagating the laser beam is provided with mirrors 12, 13, 14 and is arranged above the open pipe H. The mirrors 12 and 13 are arranged with the center of the optical path therebetween in the vertical direction, and are supported rotatably around an axis pp of the center of the optical path. A laser beam 9 emitted from a laser light source (not shown) passes through mirrors 12 and 13, and reflected light from the mirror 13 is reflected by the mirror 14.
Reach Then, the light is condensed and reflected by the mirror 14 and is applied to the abutting portion 6 of the open pipe H. At this time, the optical axis direction of the laser beam 9 with which the abutting portion 6 is irradiated is the vertical direction that is the same as the rotation axis p-p of the processing head 15.

When a welded pipe is manufactured using such an apparatus, the amount of deviation of the abutting portion 6 from the laser irradiation target position is detected, and the machining head 15 is rotated along the axis p- in accordance with this amount of deviation.
The laser beam 9 is radiated to the abutting portion 6 by rotating it around p. At this time, since the axis pp of rotation of the processing head 15 is in the vertical direction, the laser beam 9 with which the open pipe H is irradiated is always radiated vertically downward.

FIG. 11 is a schematic cross-sectional view of the state of laser beam irradiation of a conventional welded pipe as seen from the upstream side of welding. Now, when the irradiation target position of the laser beam is the top of the open pipe H and the abutting portion 6 is at a position displaced from the apex, the processing head 15 is rotated to cause the laser beam 9 to follow the abutting portion 6. . An enlarged cross-sectional view of the abutting portion 6 at this time is shown in FIGS. 12 and 13. As shown in FIG. 12, when the laser beam 9 is irradiated to the abutting portion 6, the molten metal 17 is formed in the tube wall direction from the periphery of the abutting portion 6 along the irradiation direction of the laser beam 9. The thermal energy of the formed molten metal 17 is conducted to the unmelted portion in contact with the molten metal 17, and the area of the molten metal 17 is expanded.

However, when the optical axis of the laser beam 9 is not within the abutting end face, as shown in FIG.
Since the heat conduction of No. 7 does not follow the abutting end surface 16, the amount of heat conduction from the molten portion 16B of the abutting end surface 16 to the unmelted portion 16A is reduced, and the unmelted portion 16A of the abutting end surface 16 is not melted. As a result, there is a problem that defective welding occurs in the abutting portion.

The present invention has been made in view of the above circumstances, and the energy beam is made to follow the abutting portion of the welded pipe, and heat conduction in the pipe wall direction is performed from the abutting portion to within the abutting end surface. Accordingly, it is an object of the present invention to provide a seam copying control method and a seam copying controlling device for a welded pipe that can perform welding without producing an unwelded portion.

[0011]

A seam copying control method for a beam welded pipe according to a first aspect of the present invention conveys a metal strip in a longitudinal direction, and bends both widthwise end faces into opposing open pipes, In the method of controlling the seam copying of the beam welded pipe to be welded by irradiating the energy beam propagated by the optical mechanism to the abutting part where the both end faces are abutted,
A process of detecting the seam deviation amount from the reference position of the abutting part in a plane perpendicular to the tube axis, and the seam deviation amount of the energy beam so that the optical axis of the energy beam is on a plane including the tube axis. And a step of moving the optical mechanism according to a result of the detection.

A seam copying control method for a beam welded pipe according to a second aspect of the present invention conveys a metal strip in the longitudinal direction, bends both widthwise end faces into opposite open pipes, and abuts both end faces. In the method of controlling the seam copying of the beam welded pipe that is welded by irradiating the energy beam propagated by the optical mechanism to the abutting portion, the seam deviation amount from the reference position of the abutting portion is used as the pipe axis. A step of detecting in a vertical plane, and a step of moving the optical mechanism according to the result of detection of the seam shift amount so that the optical axis direction of the energy beam matches the radial direction of the open pipe. It is characterized by being provided.

A seam copying control device for a beam welded pipe according to a third aspect of the present invention conveys a metal strip in the longitudinal direction, bends both widthwise end faces into opposite open pipes, and abuts both end faces. In the device for controlling the seam copying of the beam welded pipe that is welded by irradiating the energy beam propagated by the optical mechanism to the abutting part, the seam deviation amount from the reference position of the abutting part is used as the pipe axis. Seam deviation amount detecting means for detecting in a vertical plane, moving means for moving the optical mechanism so that the optical axis of the energy beam is on a plane including the welding tube axis, and detection of the seam deviation amount detecting means And a movement control means for giving the movement amount of the optical mechanism to the movement means based on the result.

A seam copying control device for a beam welded pipe according to a fourth aspect of the present invention conveys a metal strip in the longitudinal direction, bends both widthwise end faces into opposing open pipes, and abuts both end faces. In the device for controlling the seam copying of the beam welded pipe that is welded by irradiating the energy beam propagated by the optical mechanism to the abutting part, the seam deviation amount from the reference position of the abutting part is used as the pipe axis. A seam deviation amount detecting means for detecting in a vertical plane, a moving means for moving the optical mechanism so that an optical axis direction of the energy beam coincides with a radial direction of the open pipe, and a seam deviation amount detecting means. And a movement control means for giving the movement amount of the optical mechanism to the movement means based on the detection result.

A beam welded pipe seam copying control device according to a fifth aspect of the present invention is the beam welding pipe control device according to the third or fourth aspect of the invention, wherein the moving means includes an arcuate support guide having the tube axis as a center. It is characterized in that it is supported by a support guide and moves along the support guide in response to an input from the movement control means.

A beam welded pipe seam copying control device according to a sixth aspect of the present invention is the beam welding pipe control device according to the third or fourth aspect, wherein the moving means includes a support guide having a longitudinal direction in a direction perpendicular to the pipe axis, and the optical mechanism. The optical mechanism is supported by the support guide, moves along the support guide in response to an input from the movement control means, and rotates about the rotation axis. It is characterized by doing.

[0017]

In the seam copying control method and seam copying control apparatus for a beam welded pipe of the present invention, the abutting portion of the open pipe is irradiated so that the optical axis of the energy beam lies on a plane including the pipe axis, and Since heat conduction in the pipe wall direction is performed within the abutting end surface, the entire abutting end surface is melted and welding defects do not occur. Further, since the energy beam is irradiated from the radial direction of the open pipe and the heat conduction in the pipe wall direction of the open pipe is performed within the abutting end surface, the entire abutting end surface is melted and welding defects do not occur.

Further, in the seam copying control device for a beam welded pipe according to the present invention, the moving means is an arc-shaped support guide having the pipe axis as a center, and the pipe is moved by moving the optical mechanism along the support guide. The energy beam is irradiated so as to have the optical axis on the plane including the axis, or the energy beam is irradiated from the radial direction of the open pipe.

Further, in the seam copying control device for a beam welded pipe according to the present invention, the moving means is a support guide movable in a direction perpendicular to the pipe axis, and by moving the optical mechanism along the support guide, By rotating the optical mechanism around a rotation axis parallel to the tube axis direction, the energy beam is irradiated so that the optical axis is on the plane including the tube axis, or the energy beam is irradiated from the radial direction of the open pipe. It

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings showing the embodiments. FIG. 1 is a block diagram showing the arrangement of a seam copying control apparatus according to the first embodiment of the present invention. H in the figure
Is an open pipe, and a metal strip horizontally conveyed by various roll-forming stands (not shown) arranged in tandem in the longitudinal direction is bent into an open pipe with a circular cross section such that the end faces in the width direction face each other during this conveyance. Is made.

A contact tip (not shown) is arranged on the upstream side of the end face abutting position of the open pipe H, and the high frequency current generated by the high frequency oscillator 34 is applied to the open pipe H.
Is supplied to. In the vicinity of the end surface of the open pipe H, the seam deviation amount detecting unit 2 for detecting the seam deviation amount from the reference position.
0 is provided, and the processing head 5 which is the optical mechanism and a laser beam light source (not shown) are provided above the abutting position, and by moving the processing head 5 as described later, the open pipe is opened. The abutting portion 6 of H is irradiated with a laser beam.

FIG. 2 is a side view of the laser beam optical path system including the processing head 5 shown in FIG. 1 as seen from the side of the transport, and FIG. 3 is a front view as seen from the downstream side of the transport. The processing head 5 includes mirrors 2 and 3 having a flat surface and a mirror 4 having a parabolic surface.
And, as shown in FIG. 3, mirrors 2, 3, 4
Is located on a straight line passing through the mill center X when viewed from the front of the open pipe conveyance. This straight line is the machining head axis q-
Let q. The mirror 2 is rotatable about an axis C2-C2 in a plane including the mill center line xx, and is rotatable according to a seam displacement amount detected by a seam displacement amount detecting unit 20 described later. To be done. The mirrors 3 and 4 are fixed to the processing head 5. The machining head 5 configured as described above is supported by the support guide 8 which is the moving means and has an arc shape centered on the mill center line xx, and is detected by the seam deviation amount detection unit 20 described later. The machining head 5 can be rotated along the inner circumference in accordance with the seam shift amount.

In this embodiment, the machining head 5 is connected to the support guide 8 so as to be movable, but the present invention is not limited to this, and the machining head 5 is fixed to the support guide 8 and the support guide 8 is provided. May be rotatable about the mill center line xx.

Further, the mirror 1 is arranged on an axis s-s which vertically intersects the mill center line xx. Mirror 1
Is rotatably disposed about an axis C1-C1 in a plane including the mill center line xx and the axis s-s,
It is rotated about the axes C1-C1 according to the seam deviation amount detected by the seam deviation amount detecting unit 20 described later.

When the laser beam propagates through the laser beam optical path system configured as described above, the laser beam 9 is emitted from the laser oscillator (not shown) and is applied to the mirror 1 via the optical path tube (not shown). The laser beam 9 reflected by the mirror 1 is reflected by the mirror 2 and illuminates the mirror 3, and then is reflected by the mirror 3 and reaches the mirror 4. The mirror 4 condenses and reflects the laser beam 9 and irradiates the abutting portion 6 of the open pipe H.

At this time, as described above, the machining head 5 is rotated about the mill center line xx, and the mirror 1 and the mirror 2 are rotated about their axes C1-C1 and C2-C2. Has been done. In order to irradiate the abutting portion 6 of the open pipe H with the laser beam 9, as shown in FIG.
Seam helix angle θ in the plane where the machining head 5 is perpendicular to the pipe axis
_The mirror 1 is rotated by _{3 to} rotate the mirror 1 so that the incident / reflected angle difference of the laser beam 9 becomes θ ₁ , and the mirror 2 is rotated so that the incident / reflected angle difference of the laser beam 9 becomes θ ₂ .

At this time, the relationship of the equation (1) is established between the seam twist angle θ ₃ and the incident / reflection angle difference θ ₁ and the incident / reflection angle difference θ ₂ . θ ₃ = θ ₁ −θ ₂ (1) Since the distance between the mirror 2 and the mill center point X and the distance L between the mirror 1 and the mill center X are fixed, θ ₃ and θ ₂
Equation (2) holds between and.

[0028]

[Equation 1]

By obtaining the seam twist angle θ ₃ from these relationships, irradiation is performed so that the optical axis of the laser beam 9 passes through the abutting portion 6 of the open pipe H and lies on the plane including the mill center line xx. That is, it is understood that the optical axis direction is the radial direction of the tube when viewed from the front side of the transportation, and the irradiation angle formed with the mill center line xx is the direction of α when viewed from the side surface of the transportation. .

FIG. 4 shows the seam deviation amount detecting section 20 shown in FIG.
FIG. 3 is a block diagram showing the configuration of FIG. Seam shift amount detection unit 2
0 includes a surface thermometer 21, an abutting point position calculation unit 22, a slit light source 23, a CCD camera 24, an end face position calculation unit 25, and a control amount calculation unit 26. The surface thermometer 21 is a two-color thermometer, and supplies information on the measured temperature distribution to the abutting point position calculation unit 22. The abutting point position calculation unit 22 determines the position information of both end faces, obtains the position of the abutting point which is the intersection of the both end faces, and inputs the position of this abutting point to the control amount calculation unit 26.

On the other hand, a slit light source is provided upstream of the surface thermometer 21 for conveyance, and a CC light source is provided upstream of the slit light source 23.
A D camera 24 is provided. The image signal captured by the CCD camera 24 is input to the end face position calculation unit 25, where the positions of two end face irradiation points on the slit light irradiation position are obtained. The position of this end face irradiation point is the control amount calculation unit 26.
Is input to. The control amount calculation unit 26 calculates the position of the abutting unit 6 which is the irradiation target of the laser beam from the positions of the abutting points and the positions of the two end face irradiation points, and the open pipe H
Determine the amount of seam deviation when the top of the is the reference position.
The inventors of the present application have proposed in Japanese Patent Application No. 5-143689 a method for detecting the position of the abutting end face of an open pipe using such a seam shift amount detection unit, and details thereof will be omitted here. .

The seam shift amount detecting section 20 detects
Seam deviation amount to seam twist angle θ ₃Ask for. In addition,
The detected position of the abutting portion 6 is measured from the uppermost point of the metal pipe in the circumferential direction.
Assuming the heading distance or seam shift, sin θ₃= Seams
It is approximated by the amount of leakage / radius of welded pipe.

The seam twist angle θ ₃ obtained by the seam shift amount detection unit 20 is calculated by the machining head control unit 30 and the calculation unit 3.
1 is input. The machining head control unit 30 gives the inputted seam twist angle θ ₃ to the support guide 8 and
That is, the mirrors 2, 3 and 4 are rotated by θ ₃ about the mill center line xx. In the calculation unit 31, the above-mentioned equation (1),
Equation (2) is set, and the seam twist angle θ ₃ is input to obtain the incident / reflection angle differences θ ₁ and θ ₂ . Signals corresponding to the calculated incident / reflection angle differences θ ₁ and θ ₂ are input to the mirror control units 32 and 33, respectively. The mirror control unit 32 rotates the mirror 1 about the C1-C1 axis so that the difference between the incident and reflected angles of the mirror 1 becomes θ ₁ . The mirror control unit 33
C2-C2 so that the difference between the incident and reflected angles of the mirror 2 becomes θ _2.
The mirror 2 is rotated around the axis.

The seam copying control device having the above structure is used.
Open beam when manufacturing beam welded pipes
H is conveyed, and the seam deviation amount detection unit 20 opens
Seam deviation angle of H₃To detect and mill the machining head 5
Θ around the center line xx ₃Only rotate it. Soshi
Seam deviation angle θ₃Based on the
Reflected angle difference θ₁, Θ₂Mirror 1 and Mi
Rotate the rail 2. As a result, the mill center line xx
Toward the abutting portion 6 so that the optical axis is in a plane including
Beam that irradiates laser beam 9 to prevent welding defects
Welded pipes can be manufactured.

Next, another embodiment in which the mirror arrangement and the method of moving the processing head are different from the above-mentioned embodiment will be described. FIG. 5 is a side view of the laser beam optical path system of the seam copying control apparatus of the second embodiment as seen from the side of the carrying side, and it is shown together with functional blocks for controlling the laser beam optical path system. FIG. 6 is a front view of the laser beam optical path system as viewed from the downstream side of conveyance. As shown in the figure, a seam shift amount detection unit 40 for detecting the seam shift amount is disposed above the end face abutting position of the open pipe H.

A support guide 7 is disposed above the end face abutting position of the open pipe H with the width direction of the open pipe H as the longitudinal direction, and the processing head 35 as the optical mechanism is provided on the support guide 7. It is arranged. Processing head 35
Is provided with a cylindrical rotating part 35a having its own axis parallel to the mill center line xx, and a substantially rectangular parallelepiped beam reflecting part 35b fixed to the upstream side of the rotating part 35a in conveyance.
The rotating portion 35a has the mirror 1 having a flat surface disposed therein,
It is rotatable about a rotation axis t-t. Beam reflector 3
5b has therein mirrors 2 and 3 each having a flat surface and a mirror 4 having a parabolic surface. Then, as shown in FIG. 6, the mirrors 1, 2, 3, 4 are arranged so as to be located on the machining head axis q-q passing through the mill center X when viewed from the front of the open pipe conveyance.

The support guide 7 is provided with a parallel movement control section 37. When the parallel movement control section 37 moves in the width direction of the open pipe H, the rotating section 35a moves in parallel. As described above, the moving means includes the support guide 7, the parallel movement control unit 37, and the rotation axis t-t, and the beam reflecting unit 35.
b and the rotating portion 35a are integrally moved in parallel and rotated.

When the laser beam propagates through the laser beam optical path system configured as described above, the laser beam 9 is emitted from the laser beam source (not shown) and the mirrors 1, 2, 3, 4 are used as in the above-described embodiments. It is irradiated onto the abutting portion 6 of the open pipe H via.

At this time, the relationship of the equation (3) is established between the seam twist angle θ ₃ and the widthwise movement distance δ of the open pipe H. tan θ ₃ = δ / G (3) Here, G is the distance from the abutting portion 6 that irradiates the laser beam 9 to the support guide 7, and this is determined by the position where the support guide 7 is arranged. From this relationship, it is found that the laser beam 9 can be irradiated through the abutting portion 6 of the open pipe H so as to coincide with the radial direction of the open pipe H by obtaining the seam twist angle θ ₃ .

FIG. 7 shows the seam deviation amount detecting section 40 shown in FIG.
FIG. 3 is an elevational view showing the configuration of FIG. As shown in the drawing, the seam shift amount detection unit 40 has an arc-shaped guide base 41 centered on the mill center line xx of the open pipe H on the upstream side of the machining head 35 above the open pipe H. The support rollers 42 can roll on the guide base 41 in the width direction of the open pipe H. A guide roller 43 is connected to the lower side of the support roller 42, and the guide roller 43 is arranged between both end surfaces of the open pipe. The support roller 42 rolls on the guide base 41 by the movement of the guide roller 43 in the width direction of the open pipe H. At this time, a pulse generator (not shown) included in the support rollers 42 measures the rolling direction of the support rollers 42 and the movement amount from the reference position,
From this result, the seam twist angle θ ₃ is detected. In this embodiment, the top of the open pipe H is set as the reference position.

The seam twist angle θ ₃ obtained by the seam shift amount detection unit 40 is input to the machining head rotation control unit 38 and the calculation unit 36. The processing head rotation control unit 38 rotates the processing head 35 by θ ₃ about the rotation axis t-t. On the other hand, the above-mentioned equation (3) is set in the calculation unit 36, and the seam twist angle θ ₃ is input to obtain the moving distance δ. The calculated movement distance is input to the parallel movement control unit 37, and the processing head 35 is moved by δ in the width direction of the open pipe H.

When a beam welded pipe is manufactured using the seam copying control device having the above-described structure, the open pipe H is conveyed and the seam deviation amount detecting section 40 detects the seam deviation angle θ ₃ of the open pipe H. Then, the processing head 35 is rotated by θ ₃ about the rotation axis t-t. Then, based on the seam shift angle θ ₃ , the processing head 35 is moved in the width direction of the open pipe in accordance with the movement distance δ calculated by the calculation unit 36. Thereby, the laser beam 9 is irradiated from the radial direction of the welded pipe toward the abutting portion 6,
It is possible to manufacture a beam welded pipe that does not cause welding defects.

In the first and second embodiments described above, the processing head is provided with the mirrors 2, 3 and 4 so that the laser beam 9 is reflected at an acute angle, but the reflection angle is not limited to this. . For example, as shown in the side view of the seam copying control device in FIG.
It may be 90 °. This can also be applied to the processing head of the first embodiment.

Further, the seam copying control device of the present invention may be constructed so that the optical path length between the mirrors 2 and 3 can be adjusted according to the outer diameter of the welded pipe to be manufactured. FIG. 9 is a side view showing the processing head of the seam copying control device of the present invention.
In the figure, reference numeral 45 denotes a processing head provided with a mirror for irradiating the open pipe H with the laser beam 9, and the mirror 3
And a first head portion 45A on which the mirror 4 is arranged, a second head portion 45B on which the mirror 2 is arranged, and a processing head body 45C. The first head portion 45A is integrally formed with the processing head body 45C, and the first head portion 45A and the second head portion 45B are connected by the bellows member 46 in the optical path between the mirrors 2 and 3. . The first head 45A is connected to the processing head body 45C via the moving mechanism 47.

The seam copying control device having the above structure is
Before welding the metal pipe, the moving mechanism 47 is moved to expand and contract the bellows member 46, and the distance between the mirrors 2 and 3 can be adjusted according to the outer diameter of the welded pipe to be manufactured.

Furthermore, the seam deviation amount detecting method may be a method other than the method shown in the above-described embodiment (see FIGS. 4 and 7), as long as θ ₃ can be detected.

The results of the tests conducted on the frequency of occurrence of seam defects when a thick pipe is manufactured using the apparatus of the present invention will be described below. Table 1 shows the welding conditions used in the test.

[0048]

[Table 1]

The method of the present invention uses the apparatus shown in the first embodiment, and the conventional method uses the conventional processing head and the seam shift amount detecting apparatus disclosed in Japanese Patent Application No. 5-143689. In each of the example and the conventional example, 100 pipe materials were manufactured, and the welded portion was subjected to an X-ray transmission test. The results are shown in Table 2. The judgment was based on the judgment method of JIS Z-3104. By the determination method of JIS Z-3104, the defect-free, minute beat shape defect or blowhole state (judged as grade 1 to 3) and the defect due to seam shift (judged to grade 4) were examined. The metal strip H, which is the material of the welded pipe used in the test, was cut at a pitch of 5 m and then welded and connected again by MIG welding so that seam misalignment was likely to occur during welding.
A laser welded tube was produced using this metal strip H.

[0050]

[Table 2]

As shown in Table 2, by applying the method of the present invention, defects due to seam deviation can be reduced as compared with the conventional method, and defects (class 4) due to seam deviation are more likely to occur as the pipe is thicker. From this, it can be understood that this effect is more remarkable in a thicker beam welded pipe. Further, although the composite heat source welding method was used in this test, in the case of laser single welding, the bead width tends to be narrower than that of the composite heat source method, and the seam shift is more likely to occur. From this, it can be expected that, when the present invention is applied to laser-only welding, results exceeding the effects shown in Table 2 are obtained.

[0052]

As described above, according to the present invention, the energy beam is caused to follow the abutting portion of the welded pipe and is irradiated so that the plane including the pipe axis has the optical axis, or the radial direction of the open pipe. Since the heat conduction in the tube wall direction is performed in the abutting end surface, the seam copying is performed without causing a defective joint at the abutting end surface, and the present invention is excellent. It is effective.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a seam copying control device according to a first embodiment of the present invention.

FIG. 2 is a side view of a laser beam optical path system including the processing head 5 shown in FIG.

3 is a front view of the laser beam optical path system including the processing head 5 shown in FIG. 1 as viewed from the downstream side of conveyance.

FIG. 4 is a block diagram showing a configuration of a seam deviation amount detection unit shown in FIG.

FIG. 5 is a side view of a laser beam optical path system of a seam copying control device according to a second embodiment.

FIG. 6 is a front view of the laser beam optical path system of the second embodiment as viewed from the downstream side of conveyance.

7 is an elevational view showing a configuration of a seam deviation amount detection unit shown in FIG.

FIG. 8 is a side view of a seam copying control device according to another embodiment of the present invention.

FIG. 9 is a side view showing a processing head of a seam copying control device according to another embodiment of the present invention.

FIG. 10 is a side view showing a configuration of a processing head of a conventional laser welding device.

FIG. 11 is a schematic cross-sectional view of the state of laser beam irradiation of a conventional welded pipe as viewed from the upstream side of welding.

12 is an enlarged cross-sectional view of the abutting portion of the open pipe shown in FIG.

13 is an enlarged cross-sectional view of the abutting portion of the open pipe shown in FIG.

[Explanation of symbols]

 1, 2, 3, 4 Mirror 5, 35, 45 Machining head 7, 8 Support guide 20, 40 Seam deviation amount detection unit 30 Machining head control unit 33, 32 Mirror control unit 37 Parallel movement control unit 38 Machining head rotation control unit

Claims (6)

[Claims] 1. A metal band is conveyed in the longitudinal direction, and both end faces in the width direction are bent into open pipes facing each other, and propagated by an optical mechanism to an abutting part where the both end faces are abutted. In a method of controlling a seam copying of a beam welded pipe that is welded by irradiating an energy beam, a process of detecting a seam deviation amount from a reference position of the abutting portion in a plane perpendicular to a pipe axis, and the energy beam And a step of moving the optical mechanism according to a result of the detection of the seam shift amount so that the optical axis of the optical axis is on a plane including the tube axis. 2. A metal band is conveyed in the lengthwise direction, both end faces in the width direction are bent into opposite open pipes, and propagated by an optical mechanism to an abutting part where the both end faces are abutted. In a method of controlling a seam copying of a beam welded pipe that is welded by irradiating an energy beam, a process of detecting a seam deviation amount from a reference position of the abutting portion in a plane perpendicular to a pipe axis, and the energy beam And a step of moving the optical mechanism according to a result of detection of the seam shift amount so that the optical axis direction of the optical axis coincides with the radial direction of the open pipe. 3. A metal band is conveyed in the longitudinal direction, while the widthwise both end faces are bent into open pipes facing each other, and propagated by an optical mechanism to an abutting part where the both end faces are abutted. A device for controlling a seam profile of a beam welded pipe that is welded by irradiating an energy beam, wherein a seam displacement amount detecting means for detecting a seam displacement amount from a reference position of the abutting portion in a plane perpendicular to the pipe axis. A moving means for moving the optical mechanism so that an optical axis of the energy beam is on a plane including a welded pipe axis; and a moving amount of the optical mechanism based on a detection result of the seam shift amount detecting means. A seam copying control device, comprising: a movement control means for giving the movement means. 4. A metal band is conveyed in the longitudinal direction, and is bent by an optical mechanism to an abutting part formed by bending both end faces in the width direction into opposing open pipes and abutting the both end faces. A device for controlling a seam profile of a beam welded pipe that is welded by irradiating an energy beam, wherein a seam displacement amount detecting means for detecting a seam displacement amount from a reference position of the abutting portion in a plane perpendicular to the pipe axis. A moving unit that moves the optical mechanism so that an optical axis direction of the energy beam matches a radial direction of the open pipe; and a moving amount of the optical mechanism based on a detection result of the seam shift amount detecting unit. A seam copying control device, comprising: a movement control means for giving the movement means. 5. The moving means includes an arc-shaped support guide having the tube axis as a center, and the optical mechanism is supported by the support guide and follows the support guide in response to an input from the movement control means. The seam copying control device according to claim 3 or 4, wherein the seam copying control device moves. 6. The moving means includes a support guide having a longitudinal direction in a direction perpendicular to the tube axis, and a rotation axis provided in the optical mechanism and parallel to the tube axis, the optical mechanism including the support guide. 5. The seam copying control device according to claim 3, wherein the seam copying control device is supported by, and moves along the support guide in accordance with an input from the movement control means, and rotates around the rotation axis.