JPS649888B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for adjusting the diameter of a spiral steel pipe in the manufacture of a spiral steel pipe using an electric resistance welding method using a hot-rolled coil or a thick plate as a raw material.

(Prior Art) In the method of manufacturing spiral steel pipes, there are two conventional pipe diameter adjustment methods using arc welding: forming angle adjustment and offset adjustment. Of these, the offset amount is adjusted by adjusting the forming conditions of the inner and outer forming rolls, and by raising and lowering the side edges of the pipe-shaped strip. This method of raising and lowering the side edges of the strip is performed by keeping the left side edge level constant in the direction of progress of the strip during forming, and by adjusting the side edges of the steel pipe up and down using external forming auxiliary rolls, inner forming auxiliary rolls, etc. This can be done by forming an offset between them, or by keeping one side edge of the spiral steel tube constant and adjusting the left edge up and down in the direction of travel of the strip using an edge roll for forming the outer surface to form an offset. Ta. In recent years, electric resistance welding has been introduced into the spiral steel pipe manufacturing process with the aim of significantly improving efficiency and quality. In this case, both edges of the strip and pipe are wrapped and pressed between a pair of upper and lower pressure rolls. Since we will do
As mentioned above, it has become difficult to intentionally create an offset.

Figures 1 and 2 show the process in which the pipe diameter changes continuously by forming an offset (stepped seam) during the manufacturing of spiral steel pipes. FIG. 2 is a schematic side view of a spiral steel tube being manufactured, showing the process in which the tube diameter gradually increases due to the formation of an offset. FIG. 2 is a schematic side view of a spiral steel tube being manufactured, showing the process in which the tube diameter gradually decreases due to the formation of an offset for diameter reduction.

Figures 3, 4, and 5 are a plan view and a side view of a spiral steel pipe being manufactured, showing a pipe diameter adjustment method in the spiral steel pipe manufacturing process using the conventional arc welding method, in which 1 is a strip; 2 is a spiral steel pipe, 3 is an inner surface forming roll, 4, 5 is an outer surface forming roll, 6, 7, 8 is an outer surface forming auxiliary roll,
These are an auxiliary roll for forming the inner surface and a strip edge adjusting roll for forming the outer surface.They are separate from the inner and outer surface forming rolls 3, 4 and 5 and can be adjusted up and down independently, and an offset is intentionally formed between the strip edges or pipe edges to adjust the pipe diameter. We are making adjustments. However, in either method, only one side edge near the welding point _Wp is moved up and down, so adjustment is a process of repeated trial and error.

FIG. 6 is a plan view of a spiral steel tube showing the arrangement of pressure rolls and power supply contact chips when electric resistance welding is used, where 3 is an inner forming roll, 4 and 5 are outer forming rolls, 9 1 is a contact tip for electric resistance welding, which has a left side edge 10 of the strip 1 and a right side edge 1 of the already formed strip in the advancing direction of the strip 1.
The pressure rolls 20, 40 press the left side edges 10, 11 of the strip from above and below at a point 14 where the left side edge of the strip intersects a vertical plane passing through the tube axis of the pipe. It is pressed, formed, and welded. This actually makes it difficult to create an offset by raising and lowering the side edge 11 of the strip, and also makes it impossible to adjust the tube diameter.

(Object of the Invention) An object of the present invention is to provide a method for adjusting the diameter of a spiral steel pipe in manufacturing a spiral steel pipe, which advantageously solves the problem of offset formation due to the raising and lowering of the strip side edge 11 mentioned above.

(Utilization of structure of the invention) The gist of the present invention is to electrically resistance weld one side edge of a strip and one side edge of an already formed steel pipe in a wrapped state, and then use a pair of pressure rolls on the inner and outer surfaces to In the spiral pipe manufacturing method, in which forming welding is performed by pressing the lap portions of both side edges from the inside and outside, an internal shaft that rotates and drives is provided at a position corresponding to the inner surface of the pipe, and at least one part of the internal shaft is eccentric with respect to the axis. A pressure roll 23 is rotatably attached to the eccentric rotation surface, and a pressure roll 22 is attached to the inner shaft adjacent to the pressure roll 23 to serve as an upper pressure roll. An external shaft that is rotatably driven is provided at a corresponding position, a rotating surface eccentric to the axis is provided at least at one location on the external shaft, a pressure roll 43 is rotatably attached to the eccentric rotating surface, and pressure is applied. A pressure roll 42 is attached to the external shaft adjacent to the roll 43 to form an external pressure roll, and when there is no need to change the diameter, the pressure rolls 22 and 23 and the pressure rolls 42 and 43 are at the same level. Yes, when changing the diameter, at least one of the upper pressure roll and the lower pressure roll is moved up and down according to the strip thickness and held;
Pipe diameter in spiral steel pipe manufacturing, characterized in that the pipe circumference or pipe diameter of a formed spiral steel pipe is continuously measured and compared with a reference value, and the pair of inner and outer shafts are rotated so as to correct this difference. This is an adjustment method.

(Example) Next, an example of the present invention will be described in detail with reference to the drawings.

FIG. 7 is a partial sectional view of the pressure roll, 20,4
0 indicates a state in which the left side edge 10 of the strip and the side edge 11 of the already formed pipe are pressed from above and below in a wrapped state by an upper pressure roll and a lower pressure roll, respectively. Pressure roll 22, 23 or 42,
43 is fitted with the eccentric shafts 24 and 44, respectively, and is rotatable independently, and is fitted with a shaft that is eccentric by emm with respect to the axes 25 and 45, respectively.

This pressure roll can be used as roll 2 as another method.
Only the pressure rolls 3 and 43 are made eccentric, and the pressure rolls 22 and 42 are
be coaxial with the respective axes 25 and 45, or
Alternatively, as shown in FIG. 8, the roll on one side may be integrated with the roll shaft, and the shaft on the other side may be separated and connected to the eccentric shaft.

Note that after electrical resistance welding, arc welding is performed on the inner and outer surfaces, but a smooth welding surface is required for arc welding. For this reason, it is effective to install protruding rolls between the upper and lower rolls. That is, 21 and 41 are protruding rolls for shaping the protruding beads of the electric resistance welding part, which rotate on the same axis as the axes 25 and 45. Since the cross-sectional shape of the end of the protruding roll has a protruding bead amount that varies depending on the plate thickness, amount of lapping, etc., a preferable finished shape is selected depending on the amount of the protruding bead.

Figure 9 shows the eccentric shafts 24, 44 of the pressure roll at 0°~
This figure shows the trajectory of the pressure surfaces of the left end rolls 22, 42 and right end rolls 23, 43 when rotated by 180 degrees, the horizontal axis is the rotation angle of the eccentric shaft, and the vertical axis is the stepped amount of the pressure surface of each roll. shows. Here, when the rotation angle of the eccentric shaft is 90°, the step is zero, and when the rotation angle is 0° or 180°, the maximum step value is 2 mm. However, at 0° and 180°, the stepped direction is opposite.

FIG. 10 is a plan view showing the rotation angle drive system of the eccentric shaft of the upper pressure roll 20 attached to one end of the inner surface forming beam 15 and the inner surface forming roll 3, and FIG. 11 is a cross-sectional view taken along the line AA in FIG. It is. Here 26,
46 is a worm foil, 27, 47 is a worm shaft, 30 is a chain foil, 31 is a roller chain,
32 is a motor support arm, 33 is a support stand, 28,
48 is a drive motor (the drive motor 48 is directly connected to the worm shaft 47, but is not shown); 29;
49 is a pressure roll bearing, 34 is a hydraulic cylinder,
Reference numeral 35 designates a guide block, and the pressure roll 20 presses the both side edges with a hydraulic cylinder 34 via the guide block 35 and roll bearings 29. Reference numeral 50 is a height adjustment wedge of the lower pressure roll 40, and the height adjustment which varies depending on the pipe manufacturing size is done using an internal thread 51.
It will be held at

Figure 12 shows a device for continuously measuring the circumference of spiral steel pipes using a laser (for example,
35005) is a control system diagram when adjusting the pipe diameter using a pressure roll. This method of measuring dimensions is not particularly limited, and measurement may be performed by wrapping a tape or the like around the outer circumference of the pipe.
Here, 60 is an outer circumference measuring device, which inputs the measurement results to the arithmetic and control device C to calculate the outer circumference value. When the limit value is reached, the strip feed speed V and the eccentricity of the pressure roll are determined, and the upper The pressure roll eccentric shaft rotation drive motors 28 and 48 form a step on the pressure roll via a roller chain, a worm, and a worm wheel, thereby forming steps on both side edges and continuously changing the pipe diameter. Let's do it. In this case, the upper and lower rolls rotate synchronously in the same direction. However, the stepped formation is performed only once in the spiral pipe, and gradually returns to the pre-adjustment state and becomes stepped to zero, but if the reference value is not reached even in this state, the above operation is repeated. In this case, the amount of adjustment per movement can be freely selected within the range of 0 to 2.0 mm.

In this way, in the conventional spiral steel pipe manufacturing method using arc welding, the method involves adjusting either the strip side edge or the pipe side edge, so tube diameter adjustment is a process of trial and error. Conventionally, it has been impossible to adjust the pipe diameter in the lap welding method using a pipe, but according to the present invention, it is possible to continuously adjust the offset between the two side edges in a restrained state, and furthermore, the pipe diameter measurement results can be fed back. Automatic adjustment is now possible.

(Effects of the invention) As a result, not only labor is saved for adjusting the tube diameter, but the tube diameter can be continuously adjusted without stopping the tube manufacturing process, so stable tube dimensions can be maintained.
Further, since the adjustment is carried out gradually, a compound effect such as stabilization of the quality of the welded part can be obtained.

[Brief explanation of drawings]

Figure 1 shows a state in which the diameter of a spiral steel pipe increases continuously by forming an offset to increase the diameter at the weld seam during manufacturing of the spiral steel pipe.
The figure is a schematic side view of a spiral steel pipe being manufactured, showing a state in which the pipe diameter is continuously reduced by diameter reduction offset. Figure 3 A, B, Figure 4 A,
FIGS. 5A and 5B are a plan view and a side view during pipe manufacturing, showing a pipe diameter adjustment method in a spiral steel pipe manufacturing process using a conventional arc welding method. Fig. 6 is a plan view of a spiral steel pipe showing the arrangement of pressure rolls and power supply contact tips when electric resistance welding is used, and Fig. 7 shows the clamping state of the strip, pipe, and both side edges by the pressure rolls. 8 is a partial sectional view showing another embodiment of the pressure roll, and FIG. 9 is a locus diagram of the pressure surface when the eccentric shaft of the pressure roll is rotated. Fig. 10 is a plan view showing the rotation angle changing mechanism of the upper pressure roll attached to one end of the inner surface forming beam, Fig. 11 is a front sectional view of Fig. 10, and Fig. 12 is a combination with a pipe outer circumference continuous measuring device. FIG. 3 is an offset control system diagram. 1... Strip, 2... Spiral steel pipe, 3
...Inner surface forming roll, 4, 5...Outer surface forming roll, 6...Outer surface forming auxiliary roll, 7...Inner surface forming auxiliary roll, 8...Strip edge adjustment roll for outer surface forming, 9...Contact chip for electric resistance welding , 10...Pipe side edge, 11...Left side edge of the strip, 14...Intersection, 15...Inner surface forming beam, 20...Pressure roll, 21, 21'...Protrusion roll for bead shaping, 22, 22 '... Pressure roll (left end roll), 23, 23'... Pressure roll (right end roll), 24, 24'... Eccentric shaft, 25...
... Axis center, 26 ... Worm foil, 27 ... Worm shaft, 28 ... Drive motor, 29 ... Pressure roll bearing, 30 ... Chain wheel, 31 ... Roller chain, 32 ... Motor support arm, 33 ... …
Support stand, 34... Hydraulic cylinder, 35... Guide block, 40... Pressure roll, 41, 41'
...Protrusion roll for bead shaping, 42, 42'...
Pressure roll (left end roll), 43, 43'...pressure roll (right end roll), 44, 44'...eccentric shaft,
45... Axis center, 46... Worm foil, 47...
... Worm shaft, 48 ... Drive motor, 49 ... Pressure roll bearing, 50 ... Lower pressure roll height adjustment wedge, 51 ... Female thread, 60 ... Perimeter measuring device.

Claims (1)

[Claims] 1. Electric resistance welding is performed on one side edge of the strip and one side edge of the already formed steel pipe in a wrapped state,
Furthermore, in the spiral pipe manufacturing method, in which forming welding is performed by pressing the lap portions of both side edges from the inside and outside with a pair of inner and outer pressure rolls, an internal shaft that is rotatably driven is provided at a position corresponding to the inner surface of the pipe, and a small A rotatable surface is provided eccentrically with respect to the axis at one location in each case, a freely rotatable pressure roll 23 is attached to the eccentric rotary surface, and a rotatably freely rotatable pressure roll 22 is attached to the internal shaft adjacent to the pressure roll 23. is attached to form an upper pressure roll, an external shaft for rotational driving is provided at a position corresponding to the outer surface of the pipe, a rotating surface eccentric to the axis is provided at at least one point on the external shaft, and a rotating surface is provided on the eccentric rotating surface. A freely rotatable pressure roll 43 is attached, and a freely rotatable pressure roll 42 is attached to the external shaft adjacent to the pressure roll 43 to serve as an external pressure roll, and the upper pressure roll and the lower pressure roll are At least one of the tubes is moved up and down according to the strip thickness, and the tube circumference or tube diameter of the formed spiral steel tube is continuously measured and compared with a reference value, and the inner and outer surfaces of the pair are adjusted to correct this difference. A pipe diameter adjustment method for manufacturing spiral steel pipes, which is characterized by rotating a shaft. 2. Between the internal pressure rolls 22 and 23 and/or between the external pressure rolls 42 and 43, a protruding roll whose tip has a shape corresponding to the shape of the protruding bead is installed on the inner shaft and/or the outer shaft. 2. A method for adjusting a pipe diameter in manufacturing a spiral steel pipe according to claim 1, wherein the pipe is rotatably mounted. 3. Pipe diameter in manufacturing spiral steel pipe according to claim 1, characterized in that the internal pressure rolls 22 and 23 and/or the external pressure rolls 42 and 43 are attached to separate rotation drive shafts. Adjustment method. 4. A pipe diameter adjusting method in manufacturing a spiral steel pipe according to claim 1, characterized in that the protruding roll is fixed to the internal pressure roll 22 and/or the external pressure roll 42.