JPH05104272A - Welding equipment for manufacturing pipe - Google Patents

Abstract

PURPOSE:To provide the welding equipment for manufacturing the pipe of simple constitution by profiling the beam projection position by rollers and an arm following a gap of an open pipe. CONSTITUTION:A torch pedestal 22 is supported rotatably on an axis 23 of a fixed member 24. A plasma torch 16 is inserted into coupling 26 of the torch pedestal 22 and the arm 25 is constituted freely rotatably with a high energy density beam 20 as a center. A first guide roller 27 and a second guide roller 28 to travel along the gap 1 of the open pipe 6 are provided on the bottom of this arm 25, the plasma torch 16 profiles surely a weld line 1 of the pipe 6 and a sound welded pipe can be stably manufactured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welding machine for pipe making in which a high energy density beam is accurately positioned at a welding position when a welded pipe is manufactured using a laser welder or a plasma welder.

[0002]

2. Description of the Related Art By passing a metal strip between molding rolls, the edges are gradually formed into a shape of a molding tube (called an open pipe) in which both edges face each other with a predetermined narrow gap. A welding pipe forming method is known in which a laser beam or a plasma flow (collectively referred to as a high energy density beam in the present specification) is projected at a matching position to produce a pipe. In this case, the pipe is continuously moved in the axial direction without moving the welding machine, and the high energy density beam is projected onto the continuously moving welding position (narrow gap of the open pipe).

In such a welded pipe forming method, a high energy density beam must be accurately projected at the welding position. As a method of automatically detecting the welding position and automatically controlling the welding head to a predetermined position, for example, Japanese Patent Application Laid-Open No. 3-8107
A method of optically detecting the welding position and correcting the irradiation position as seen in Japanese Patent No. 9 and a disk-shaped roller that tracks the gap of the open pipe as proposed in Japanese Patent Laid-Open No. 1-118392. The mechanical method of doing this is known.

The latter device for mechanically copying the welding line has a simpler device configuration and easier operability than the former optical device, and also has a temporal property between the detection position and the welding position. Since there is no significant delay, the problem of temporal deviation due to welding speed does not occur.

[0005]

[Problems to be Solved by the Invention] The former Japanese Patent Laid-Open No. 3-81079
In the type that optically detects the welding position as in Japanese Patent Publication, the position detection time, the signal processing time for determining the welding position, and the welding head movement time for beam position correction are required. There is an upper limit on the welding speed that can be followed. In addition, the sensor is generally affected by the shape of the plate edge, scratches on the edge, surface condition, material, etc., so adjustment is required every time the material or shape of the welding material is changed. Since the sensor position and the welding position are different, the timing of moving the welding head must be changed for each welding speed.

On the other hand, in the device for mechanically copying the welding line proposed in Japanese Patent Laid-Open No. 1-118392, there is no time lag between the detection position and the welding position, so that the welding speed depends on the welding speed. It has the feature that the problem of temporal deviation does not occur,
And the device configuration is simpler than the former optical one,
The operability is also simple.

However, such a conventional mechanical copying device for welding lines has the following problems. FIG. 1 shows the principle of this type of device, which moves in the direction of the arrow along the pipe axis while being formed into an open pipe with its edges abutting with a predetermined gap 1 by a forming roll (not shown). The laser beam 3 is applied to the welding point 2 of the material to be welded. At that time, the welding head body 4
Is rotatably supported around a fixed shaft 5 parallel to the projected laser beam 3, and a guide roller 7 that travels between the gaps of the open pipe 6 up to the welding point 2,
It is attached to the arm member 8 protruding from the welding head body 4. According to this, even if the gap of the open pipe 6 swings to the left and right, the guide roller 7 moves to the left and right according to the swing, and the laser beam 3 also moves to the left and right accordingly, so welding that follows the welding line can be performed. Is to say.

However, as shown in FIG. 2, when the fixed shaft 5 is located on the line 1 of the open pipe 6 and the line corresponding to the gap 1 or the line adjacent thereto, the laser beam 3 is placed at the welding point. It can be irradiated, but as shown in Figure 3,
When the virtual extension line 10 of the center line of the gap 1 is largely displaced from the fixed shaft 5, the center position of the laser beam 3 existing on the straight line 11 connecting the guide roller 7 and the fixed shaft 5 is the virtual extension line. The deviation from the line 10 makes it impossible to irradiate the exact welding point of the gap 1.

On the other hand, if a pendulum type support mechanism as shown in FIG. 4 is adopted, it is possible to avoid the above-mentioned deviation between the welding point and the beam irradiation position. That is, the fixing member 13
Parallel to the tube axis (actually on a vertical plane containing the horizontal tube axis)
A fixed shaft 14 is provided, and a welding head 16 is provided so that the high energy density beam 15 swings like a pendulum with respect to the fixed shaft 14.
Attach. In the illustrated example, a plasma torch 16, which is a welding head, is vertically fixed to a vertical rod 17, the rod 17 is rotatably supported around a fixed shaft 14, and a guide roller 18 is attached to the lower end of the rod 17. Here is an example: According to this, even if the gap 1 of the open pipe swings to the left and right, the rod 17 also swings accordingly, and the plasma projection flow 15 follows the gap 17 as well.
Move on the line.

However, in this case, as shown in FIG. 5, a state in which the gap 1 is located on a plane perpendicular to the center of the fixed shaft 14.
When moving from (a in FIG. 5) to a position deviated from the vertical plane ((b) in FIG. 5), as shown in the enlarged view of FIG. The projection flow 15 will hit. In this case, heat may not be evenly applied to the edge end faces forming the gap 1, which may cause defective welding to cause welding defects.

The present invention is intended to solve the above problems in the conventional mechanical welding line copying apparatus using the guide rolls.

[0012]

According to the present invention, an arm rotating around a projected high energy density beam axis is installed in a welding head body of a high energy density beam projection type welding apparatus, and this arm is mounted on the arm. At least two disk-shaped guide rollers for tracking the welding position of the shaping pipe are attached, and these guide rollers are separated from each other in a plane whose center planes pass through the high energy density beam axis. Mounted to the arm so that the welding head itself is rotatably supported about a fuselage support axis parallel to the projected high energy density beam axis and fixed in position. A welding device for pipes is provided.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 7 is an overall view showing an embodiment of the welding apparatus for pipe making according to the present invention, and FIG. 8 is a side view thereof. This device projects a plasma flow (called a high energy density beam) 20 into the gap 1 of the open pipe 6 by a plasma torch 16 which is a welding head. The open pipe 6 is gradually formed into a tubular shape by passing a metal strip between the forming rolls (not shown) as in the case of the conventional example described above, and continuously moves in the direction of the arrow in the figure. The plasma torch 16 projects the high energy density beam 20 toward the gap 1 of the open pipe 6 which continuously moves along the tube axis, whereby the weld seam 9 is formed. An open pipe 6 is formed on the upstream side (non-welded side) of the welding point 2, and the downstream side of the welding point 2 is a welded pipe.

7 to 8, the plasma torch 16 is installed so as to be substantially vertical, and the high energy density beam 20 is vertically projected to the center of the lower end of the plasma torch 16. Such a plasma torch 16 itself is a known one. In the present invention, the plasma torch 16 is vertically fixed to the torch base 22, and the torch base 22 is parallel to the high energy density beam axis and is fixed around a fixed shaft (body support shaft) 23 whose position is fixed. It is rotatably supported. In the illustrated example, a fixed shaft 23 is fixed to the fixed member 24 vertically, and the torch base 22 is rotatably supported by the fixed shaft 23. Not limited to this example, the fixed shaft 23 may be rotatably attached to the fixed member 24, and in any case, the plasma torch 16 can be rotated around the fixed shaft 23 whose position is fixed, and thus high energy. The central axis of the density beam may be rotatably supported.

On the other hand, an arm 25 is attached so as to be rotatable around the central axis of the high energy density beam 20. In the example shown,
An example is shown in which the coupling 26 is attached directly below the torch base 22, the plasma torch 16 is inserted into the coupling 26, and the arm 25 is rotatably attached to the coupling 26. The central axis of the coupling 26 coincides with the central axis of the high energy density beam 20, and the arm 25 is rotated around the coupling 26 so that the arm 25
Rotates about the central axis of the high energy density beam 20.

A first guide roller 27 and a second guide roller 28, which run along the gap 1 of the open pipe 6, are attached to the lower surface of the arm 25. These guide rollers 27 and 28 are both disc-shaped rollers, and are arranged on the arm 25 so that their center planes are located apart from each other in the plane passing through the central axis of the high energy density beam 20. Mounted. In the illustrated example, both rollers 27 and 28 are mounted on a lower surface of an arm 25 that extends in the same horizontal direction as the tube axis on a line extending linearly from the central axis of the high energy density beam 20. That is, the nearer first guide roller 27 is located on the straight line connecting the farther second guide roller 28 and the center line of the high energy density beam 20.

With this structure, the guide rollers 27 and 28 can rotate about the high energy density beam shaft 20 at the same time, and the high energy density beam shaft 20 can rotate about the fixed shaft 23. However, since the plasma torch 16 itself is fixed to the torch base 22 that moves in the horizontal direction,
The vertical movement of the high energy density beam 20 is also suppressed by the rotation.

9 to 10 are for explaining the following operation of the welding position by the apparatus of the present invention in the preceding example. FIG. 9 shows a state in which the central axis 30 of the fixed shaft 23 is located on the welding line. In this case, the high energy density beam axis 20
The first guide roller 27 and the second guide roller 28 are also located on the same line. From this state, when the gap 1 of the open pipe 6 is displaced as shown in FIG. 10 (in the figure, the state is shown moving to the lower side of the drawing), the guide rollers 27 and 28 both move in parallel along the gap 1. To do. That is, since the guide rollers 27 and 28 are rotatably supported around the two shafts 20 and 30, the guide rollers 27 and 28 can be moved in parallel along the gap 1, and the height of the guide rollers 27 and 28 can be increased along the line connecting the guide rollers 27 and 28. Since the energy density beam axis 20 is located, the high energy density beam axis 20 is located above the gap 1.

This principle will be specifically described with reference to FIG. 11. A straight line a passing through the center planes of the disks of the guide rollers 27 and 28.
Is rotatable about the point 20, and the straight line b connecting the points 23 and 20 is rotatable around the point 23. Therefore, the straight line a is parallel to the straight line c passing through the point 23 and parallel to the tube axis. Since the high energy density beam axis 20 is located on this straight line a, it is possible to accurately project the high energy density beam into the gap between the straight lines a guided by the guide rollers 27 and 28. become. Therefore, the problem of deviation of the high energy density beam axis with respect to the welding point as described with reference to FIG. 3 does not occur.

FIG. 12 shows an embodiment of a laser beam welding head according to the present invention. In this example, the projected high energy density beam 20 is called a laser beam, but the nozzle 31 of this laser beam exists in the position of the plasma torch 16 described above.

The welding head main body 4 may be a known one as described with reference to FIG. 1, and the main body 4 rotates around a fixed shaft (vertical main body supporting shaft) 5 attached to the fixing member 32. Be movably supported. The laser beam guided by the laser beam oscillator 33 passes through the fixed support shaft 5 and then changes its direction by the mirror 34 in the main body 4, converges by the concave mirror 35, passes through the welding nozzle 31 and becomes a high energy density beam 20. It is projected on the gap of the open pipe 6.

A coupling 26 is put on the welding nozzle 31 which projects vertically downward from the welding head body 4. The central axis of this coupling 26 coincides with the high energy density beam axis 20. An arm 25 is rotatably attached to this coupling 26 in the same relationship as in the case of plasma welding in the previous example, and a first guide roller 27 and a second guide roller 28 are attached to this arm 25 in the same relationship as in the previous example. Be done. Therefore, also in this example, the guide roller 27
And 28 are rotatable about the high energy density beam axis 20 at the same time, and the high energy density beam axis 20 is rotatable about the fixed support shaft 5, so that the guide rollers 27 and 28 can be rotated as described in the previous example. Even if the gap of the open pipe guided by is displaced, the high energy density beam 20 is accurately projected onto the welding line of the gap.

FIG. 13 shows a guide roller 27 for the arm 25.
(Or 28) is attached elastically. The disk-shaped guide roller 27 (or 28) has an axis at its center.
The shaft 37 is supported by 37, and both ends of the shaft 37 are rotatably suspended by the bearing 38. This bearing 38 is an arm with the shaft 37 suspended.
It is elastically supported with respect to 25. That is, in this example, a leg member 39 having a recessed space at the lower end opening is fixed to the lower surface of the arm 25, and a support member 41 of the bearing 38 is vertically moved in a slide groove 40 provided on the inner wall of the recessed space of the leg member 39. It is slidably fitted in. A spring is provided between the bearing support member 41 and the abutting surface 42 of the recess space of the leg member 38.
43 is installed. With this, open pipe 6
The guide roller 27 (or 28) is always elastically biased against the gap 1 of the above, and even if the width of the gap 1 fluctuates slightly or the position of the gap 1 slightly fluctuates up and down, Roller 27 (or 28) is in close contact with gap 1 and shaft 37
Rotate around. As a result, the gap 1 and the guide roller
Since a gap is prevented from being formed between 27 (or 28), an accurate guide function can be exhibited.

Further, as shown in FIG. 13, the guide roller 27
By forming a disk (or 28) that becomes thinner toward the periphery of the circle, even if the width of the gap 1 changes, both edges of the gap 1 will always be in contact with each other, and a more accurate guide will be provided. Exert function.

Further, as shown in FIGS. 8 and 12, by increasing the radius of the second guide roller 28 on the far side from the radius of the first guide roller 27 on the side closer to the high energy density beam 20, It is possible to cope with the difference in opening of the gap 1 of the open pipe 6 and the difference in the vertical position of the gap 1 where both rollers are located.

The present inventors formed a 5 mm-thick SUS304 steel strip into an open pipe with a forming roll and performed plasma welding on a pipe having an outer diameter of 48.6 mm to 60.5 mm with a welding device shown in FIG. A test for pipe making was performed. The welding speed is 0.3 m / min. The line of the gap to be welded of the open pipe fluctuated 2.0 mm in the direction perpendicular to the pipe axis, but no penetration failure was observed. On the other hand, when welding was performed using the pendulum type plasma torch shown in Fig. 4 under the same conditions, when the line of the gap to be welded of the open pipe fluctuated 1.0 mm in the direction perpendicular to the pipe axis, the penetration failure rate ( The ratio of the length that caused welding failure to the total welding length) was 40%, and the gap was 2.0 m.
When there was a change in m, the penetration failure was 100%. Similarly, the same test was performed with the laser welding apparatus according to the present invention shown in FIG. 12 except that the welding speed was 3.0 m / min, and the line of the gap to be welded fluctuated 1.0 mm in the direction perpendicular to the pipe axis, but melted No defects occurred.

[0027]

According to the apparatus of the present invention, the conventional apparatus shown in FIGS.
Compared with the one-point welding line copying method shown in Fig. 3, it is possible to prevent the occurrence of welding defects due to the displacement of the welding position, and to manufacture a sound welded pipe in a stable manner. In addition, the device configuration is simple and excellent in operability as compared with the one that optically detects the welding position.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a conventional mechanical welding line copying type laser welding apparatus.

FIG. 2 is a schematic plan view for explaining a welding position of the welding device in FIG.

3 is a schematic plan view for explaining a welding position shift of the welding apparatus in FIG. 1. FIG.

FIG. 4 is a perspective view of a plasma welding apparatus showing another example of the conventional mechanical welding line copying method.

5 is a schematic front view for explaining a welding position of the apparatus of FIG.

FIG. 6 is a schematic cross-sectional view of a welded portion for explaining a cause of a defective penetration in the apparatus of FIG.

FIG. 7 is a perspective view showing an example of a plasma welding machine according to the present invention.

FIG. 8 is a schematic side view showing an example of a plasma welding machine according to the present invention.

9 is a schematic plan view for explaining a welding position of the apparatus of FIGS.

FIG. 10 is a schematic plan view for explaining changes in the welding position of the apparatus of FIGS.

FIG. 11 is a diagram for explaining the principle that the high energy density beam irradiation position follows changes in the welding position of the apparatus of FIGS.

FIG. 12 is a schematic side view showing an example of a laser welding apparatus according to the present invention.

FIG. 13 is a cross-sectional view showing an example of the elastic support mechanism of the guide roller according to the present invention.

[Explanation of symbols]

 1 Open Pipe Gap 2 Welding Point 4 Laser Welding Head Main Body 5 Body-Supported Fixed Axis 6 Open Pipe 9 Weld Seam 16 Plasma Torch 20 High Energy Density Beam 22 Torch Stand 23 Body-Supported Fixed Axis 24 Fixed Member 25 Arm 27 First Guide roller 28 Second guide roller 31 Welding nozzle 38 Bearing 43 Spring

Claims (6)

[Claims] 1. A welding head main body in a high energy density beam projection type welding apparatus is provided with an arm that rotates around a projected high energy density beam axis, and this arm is for tracking the welding position of a shaping pipe. At least two disk-shaped guide rollers are mounted on the arm so that the center surfaces of the disks are located apart from each other in a plane passing through the high energy density beam axis, A welding device for pipe making, wherein the welding head itself is rotatably supported about a machine body support axis parallel to the projected high energy density beam axis and its position is fixed. 2. The welding apparatus for pipe making according to claim 1, wherein the high energy density beam is plasma, and the welding head is a plasma torch. 3. The welding apparatus for pipe making according to claim 1, wherein the high energy density beam is a laser beam, and the welding head is a laser beam irradiation device. 4. The pipe-making machine according to claim 1, wherein two guide rollers are attached to the arm, and these guide rollers are attached to the arm in such a positional relationship that they are sandwiched in the butt gap of the open pipe before moving to the welding position. Welding equipment. 5. The welding apparatus for pipe making according to claim 1, wherein the rotation axis of the guide roller is elastically supported by the arm. 6. The welding device for pipe making according to claim 1, 4 or 5, wherein the guide roller is a disk whose thickness decreases toward the circumference of the circle.