JPH03268874A - Manufacture of spiral steel pipe and edge preparation device - Google Patents

Abstract

PURPOSE:To increase the welding speed of cladding by main welding and to obtain the spiral steel pipe with high productivity in performing cladding by main welding on the outside by cutting a tack-weld zone to form a groove before that. CONSTITUTION:Hoop 2 is supplied form the diagonal direction to the axial center of the spiral steel pipe 1 to be manufactured and the hoop is wound spirally so that both side lines thereof are made in an abutted state to manufacture the pipe. The outside of a butt part thereof is then tack-welded 4 and then, cladding by main welding 5 is performed on the inside of the butt part. The outside of the butt part including the tack-weld zone 4 is then cut in a V-shape by a cutter to form the groove 6. Lastly, cladding by main welding 7 on the outside is performed on the groove 6. Consequently, the welding speed of cladding by main welding on the outside can be increased and the productivity is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing a spiral steel pipe and a beveling device used therein.

2. Description of the Related Art Conventionally, when manufacturing a spiral steel pipe, as shown in FIG. Tack welding 53 is performed on the outside (process b), then main overlay welding 54 is performed on the inside of the butt part (step c), and finally main overlay welding is performed on the tack weld 53 on the outside of the butt part. 55 is carried out, thereby obtaining a spiral steel pipe 51 in which the inner and outer sides of the abutting portions of both side edges of the steel strip 52 are joined by main overlay welding 53 and 55.

Problem to be Solved by the Invention However, in the method for manufacturing a spiral steel pipe described above, when performing the main overlay welding 55 on the outside, the main overlay welding is performed from above the tack weld 53, so the tack weld 53 is melted. Since it takes time to secure the amount of heat input to melt the tack weld 53 and its vicinity, it is necessary to increase the welding speed of the main overlay weld 55 on the outside. Therefore, there was a problem in that the productivity of the spiral steel pipe 51 could not be increased.

SUMMARY OF THE INVENTION In view of the above-mentioned conventional problems, it is an object of the present invention to provide a method for manufacturing a spiral steel pipe that can increase the welding speed of the outer main overlay welding, and a groove device used therein.

Means for Solving the Problems In order to achieve the above object, the method for manufacturing a spiral steel pipe of the present invention involves winding a steel strip in a helical manner so that both edges of the steel strip abut against each other, and temporarily wrapping the outside of the abutting portion. It is characterized by the following: first welding, then main overlay welding on the inside of the butt part, then cutting the outer tack welded part in a V-shape to form a groove, and then performing main overlay welding on the outside. shall be.

Further, the present invention provides a device for forming the groove, including a movable table movable in the direction of the tube axis, a cutting table movable in the direction perpendicular to the tube axis, and a movable table movable in the direction of the tube axis. To provide a swivel table that is rotatable around a rotation axis, and a cutter that can be rotated around an axis perpendicular to the rotation axis and whose center is located on the rotation axis.

Effects According to the above configuration, the tack weld is cut to form a groove before performing the main overlay welding on the outside, so the main overlay on the outside can be welded without melting the tack weld. Overlay welding can be performed, the welding speed of main overlay welding can be increased, and spiral steel pipes can be manufactured with high productivity.

Moreover, according to the beveling device configured as described above, the steel strip is spirally wound in the pipe making line, and the beveling is performed on the spiral steel pipe after tack welding on the outside and main overlay welding on the inside. It is possible to form Each can be handled by adjusting the position, and the above manufacturing method can be easily applied to any spiral steel pipe.

EXAMPLE Hereinafter, an example of the present invention will be described based on FIGS. 1 to 7.

First, the manufacturing process of a spiral steel pipe will be explained with reference to FIG. First, the steel strip 2 is supplied from an oblique direction to the axis of the spiral steel pipe 1 to be manufactured, and the steel strip is spirally wound so that both edges abut each other. manage

Next, after tack welding 4 is performed on the outside of the butt portion (step b), main overlay welding 5 is performed on the inside of the butt portion (step C). Next, the outer side of the abutted portion, including the tack welded portion 4, is cut into a V-shape using a cutter to form a groove 6 (step d). Finally, the outer main overlay welding 7 is performed on the groove 6 (step e).

In this way, when performing the main overlay welding 7 on the outside of the butt part, by forming the groove 6 in front of it and scraping off the tack weld 4, this main overlay welding 7 can be replaced with the main overlay welding 7 on the inside. Similar to 5, high-speed welding can be performed, and the spiral steel pipe 1 can be manufactured with high productivity.

Next, the groove device 10 for forming the groove 6 will be explained with reference to FIGS. 2 to 7.

In FIGS. 2 to 4, 11 is a movable table that can be positioned and moved to any position in the axial direction (X direction) of the spiral steel pipe 1, which is formed by spirally winding a steel band. The spiral steel pipe 1 is supported so as to be movable diagonally above along a guide rail 13 provided on a base 12 disposed on one side of the spiral steel pipe 1, and is connected to an X-axis circumferential servo motor 14 and a feed screw. It is moved and driven by a mechanism 15. 16
is a cutting table supported so as to be positionable and movable at any position along a guide rail 17 provided in the vertical direction (Z direction) on the movable table 11, and the Z-axis circumferential servo motor 1
8, a transmission means 19 consisting of a belt and a pulley, and a feed screw mechanism 20 to drive it up and down. 21 is a hydraulic cylinder for a balancer of the cutting table 16. The bearing 2 is installed in the cutting table 16.
A pivot shaft 23 is supported so as to be able to rotate about an axis perpendicular to the axis of the spiral steel pipe 1 via a pivot shaft 23, and a pivot table 24 is fixed to the lower end of the pivot shaft 23. 25 is the pivot axis 2
3 is an encoder that detects the rotational position, 26 is a rotation axis 23
This is a transmission means for interlocking the encoder 25 with the encoder 25. A swing lever 27 is fixed to the upper part of the swing shaft 23, and is driven to swing by a hydraulic cylinder 28.

The swivel base 24 is provided with a rotating shaft 30 that is rotatably supported by a bearing portion 29 around an axis perpendicular to the swivel axis. A cutter 31 is attached to the rotary shaft 30, and a pulley 35 driven by a drive motor 32 via a pulley 33 and a belt 34 is attached to the other end of the rotating shaft 30.

In order to accurately form a groove 6 in the tack weld 4 portion of the spiral steel pipe 1, the cutter 31 is used as shown in FIG.
The position is adjusted in the X direction so as to follow this tack welding 4.

Therefore, 7. (In the direction across the tack welding 4 on the movable base 11 or the cutting base 16 or the turning base 24 (
A laser sensor 36 is attached to detect the height of each point by scanning in the X direction), and its detection signal is input to the control section 37. The control unit 37 is configured to drive and control the X-axis circumferential servo motor 14 to adjust the movement of the movable base 11 in the X direction, and to position the cutter 31 at the center position of the tack weld 4.

In addition, in order to adjust the position of the cutter 31 in the Z direction according to the actual height of the portion of the spiral steel pipe 1 where the groove 6 is to be formed, and to appropriately regulate the groove depth, the steps shown in FIG. As shown in FIG. 7, a pair of detection points 38 are provided on both sides of the spiral steel pipe 1 of the cutter 31 in the circumferential direction, and the height positions of the pair of detection points 38 are determined by the detection point 38 at the tip, as shown in FIG. Detection is performed using a moving shaft 39 to which a detection sphere 39a that comes into contact with is attached, and a potentiometer 40 that detects the amount of moving forward and backward. Then, the output signals of the pair of potentiometers 40 are inputted to the control section 41, and the control section 41 receives the detected detection points 38 on both sides of the cutter 31.
Assuming a virtual surface of the spiral steel pipe 1 between the height positions of configured to adjust the position.

In the beveling device 10 having the above configuration, the spiral steel pipe 1
Since the position of the cutter 31 in the X direction is determined by the diameter of the bore and the width of the steel strip 2 used therein, the X-axis peripheral servo motor 14 is driven accordingly to position the cutter 31 in the X direction. While detecting the position with the encoder 25, the hydraulic cylinder 28 is driven and controlled to adjust the rotation position of the swivel base 24, and the direction of the cutter 31 is adjusted to the wrapping angle of the steel strip 2, thereby moving the cutter 31 to the spiral steel pipe 1. along the movement trajectory of the tack welding 4. Then, while the cutter 31 is rotationally driven by the drive motor 32, the Z-axis circumferential servo motor 18 lowers the cutter 31 to a predetermined height position, so that the cutter 31 forms a bevel 6 in the tack weld 4 portion. can be formed.

In addition, in the actual pipe manufacturing process of "spiral steel pipes", the X-direction position and Z-direction value of the tack weld 4 constantly fluctuate, but as described above, these fluctuations are detected by the laser sensor 36 and potentiometer 40. By adjusting the positions of the movable table 11 and the cutting table 16, an appropriate groove 6 can be formed.

Effects of the Invention According to the method for manufacturing a spiral steel pipe of the present invention, as described above, the tack welded portion is cut to form a groove before performing the outer main overlay welding, so that the tack welded portion is The outer main overlay welding can be performed without melting the outer main overlay welding, and the welding speed of the outer main overlay welding can be increased, making it possible to manufacture spiral steel pipes with high productivity. .

Further, according to the groove device of the present invention, a groove can be formed in a spiral steel pipe after tack welding on the outside and main overlay welding on the inside, and it is also possible to form a groove in a spiral steel pipe after performing tack welding on the outside and main overlay welding on the inside, and also to prevent changes in the width of the steel strip. Adjustments can be made by adjusting the position of the movable table for changes in groove depth, the cutting table for changes in groove depth, and the swivel table for changes in the wrapping angle of the strip, so that any desired adjustment can be made. The above manufacturing method can be easily applied to spiral steel pipes.

[Brief explanation of drawings]

Fig. 1 is a manufacturing process diagram of a spiral steel pipe according to an embodiment of the present invention, Fig. 2 is a front view of the beveling device, Fig. 3 is a right side view of Fig. 2, and Fig. 4 is a diagram of the manufacturing process of a spiral steel pipe according to an embodiment of the present invention. 5 is a plan view showing the state of beveling by the cutter, FIG. 6 is a schematic diagram of the positioning device of the cutter, FIG. 7 is a schematic diagram of the cutting depth control device, and FIG. The figure is a manufacturing process diagram of a conventional spiral steel pipe.

Claims (1)

[Claims] 1. A steel strip is spirally wound so that both edges of the band abut against each other, and the outside of the abutted portion is tack welded, and then the inside of the abutted portion is overlaid welded, Next, after cutting the outer tack weld into a V-shape to form a groove,
A method for manufacturing a spiral steel pipe, characterized by performing main overlay welding on the outside. 2. A movable table movable in the direction of the tube axis, a cutting table movable in the direction perpendicular to the tube axis, and a swivel table capable of rotating around a rotation axis perpendicular to the tube axis. 1. A bevel device comprising: a cutter that can be rotated around an axis perpendicular to the rotation axis and whose center is located on the rotation axis.