JP3525839B2 - Method and apparatus for manufacturing steel pipe - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel pipe manufacturing method for sizing an electric resistance welded steel pipe to manufacture a round steel pipe having high dimensional accuracy, and a process of reshaping the round steel pipe into a square steel pipe subsequent to this round steel pipe manufacturing process. TECHNICAL FIELD The present invention relates to a steel pipe manufacturing method for manufacturing a hand-angled steel pipe and a manufacturing apparatus thereof.

[0002]

2. Description of the Related Art In a line in which a square steel pipe manufacturing device is connected to an electric resistance welded steel pipe manufacturing line, a skelp is bent into a circular raw pipe, seam welded, and a circular electric resistance welded steel pipe is formed with a squeeze roll and a sizer roll. The electric resistance welded steel pipe is sequentially formed by a reshaping roll into a square steel pipe, and the square steel pipe is delivered from the line. Such an electric resistance welded steel pipe production line can be used as a round steel pipe production line by passing through the reshaping process. FIG. 10 shows an outline of such a line. The skelp 100 has a molding step 101.
In the welding process 102, the seam is welded to form a circular pipe, and in the sizing process 103, a round steel pipe is formed into a round steel pipe. In the cold forming process 104, a rectangular cross section is formed. It becomes the square steel pipe 106.

Conventionally, the corner shape of the square steel pipe thus formed is measured by an operator by applying a 1/4 circumference gauge having a diameter of 1 mm to the outer surface of the corner of the square steel pipe. Had been detected by measurement. The square steel pipe to be measured has a size of 250 to 550 mm square and a plate thickness of 6 to 22 mm.
Measurement by human power at the corners using such a circumferential gauge requires a line stop because the circumferential gauge is pressed against the line gauge, which causes a decrease in the line operating rate and a decrease in yield due to the line stop. It was. Moreover, since the circumferential gauge is made in stages with a pitch of 1 mm, for example, the intermediate value is determined by the scale interval of the measurer.
Individual differences tended to occur, measurement accuracy was poor, and it was time-consuming. In addition, the adjustment of the reshaping roll in the cold forming process based on the measurement results depends on the operator's technique and is not quantified, so it is difficult to perform standardized appropriate adjustment in a short time. It was

In the reshaping line, a plurality of reshaping rolls in which four rolls are arranged around the circumference of an electric resistance welded steel pipe are used, and the four rolls of the reshaping roll press the square steel pipe from four directions to form a corner. By forming four flat surfaces on the outer periphery of the steel pipe, four corner-shaped arc-shaped portions are formed in a portion adjacent to the four flat surfaces, thereby forming a circular electric resistance welded steel pipe into a square shape. Therefore, it is necessary to finely adjust the four reshaping rolls so that the arcuate portions of the four corners have the same curvature.

The corner portion of the square steel pipe is accurately shaped,
In order to stably manufacture an accurate square steel pipe, it is necessary to continuously measure the corner shape and adjust the roll.
Therefore, the present inventors have previously filed Japanese Patent Application No. 11-178348.
In the Japanese patent application, a method was proposed in which the shape of the corner portion of the square steel pipe was measured online immediately after the completion of the reshaping, and the reshaping roll was adjusted so that the measured value was within the allowable limit. At the same time, a measuring device that is installed on the outlet side of the square steel pipe manufacturing line and measures the profile of the corner portion of the square steel pipe, a calculation device that analyzes the measured values to calculate the curvature, and all corners based on the calculation results. Provided is an apparatus for forming a square steel pipe, which is provided with an automatic position adjusting device that adjusts a relative position of a reshaping roll so that a curvature of a corner matches a set curvature.

[0006]

[Patent Document 1] Japanese Patent Application No. 11-17
Although the technology of the 8348 application has achieved automation of the reshaping process, the rolls of the reshaping process may interfere intricately with each other and the adjustment may not be uniquely determined. In some cases, the precision did not reach the level of satisfactory satisfaction.

The present invention aims to improve the accuracy of the product shape by further improving the above-mentioned automation technology, and also to improve the shape accuracy of an electric resistance welded steel pipe (circular steel pipe) having a circular cross section. That is, in a line for reshaping a round steel pipe into a square steel pipe subsequent to forming the round steel pipe, the shape precision of the round steel pipe is first increased to improve the precision of the shape of the square steel pipe, and this is reshaped, and the square steel pipe is not manufactured. Sometimes it was possible to manufacture round steel pipes with high shape accuracy by omitting the reshaping process.
The purpose of the present invention is to develop a steel pipe manufacturing method and apparatus and to provide the same.

[0008]

The present invention has been made to solve the above problems, and is characterized by the following technical means. That is, the first aspect of the present invention
The invention, when molding the Sukerupu the ERW steel pipe having a circular cross section and sized to produce a round steel tube, 1 or more single
The optical axis of the three-dimensional laser rangefinder is aligned with the measuring direction
Then, rotate the pipe in the circumferential direction to make a professional round steel pipe after sizing.
The field is continuously measured online and the circumference and length of the round steel pipe are measured.
・ Horizontal / diagonal diameter, roundness, pass line, roll caliber type
The sizing roll position, steel pipe dimensions, roll setting accuracy, and sheet are calculated so that the calculated values are within the allowable limits.
Presence of twist, shear cut, material characteristics, mill center
Is a method for manufacturing a steel pipe, which is characterized by adjusting the pipe-making conditions such as the unevenness and the roll calvary . By this method, the accuracy of the round steel pipe can be improved.

[0009] The second aspect of the present invention, when the to re shell <br/> Ipingu the molded sizing dorsal horn steel pipe ERW steel pipe having a circular cross section Sukerupu, one or more one-dimensional laser distance
Arrange the optical axis of the meter so that it matches the measuring direction, and rotate it in the tube circumferential direction.
By moving continuously measuring the shape of round steel pipe after sizing online, the measured value to adjust the sizing condition to be within acceptable limits, the shape of the intermediate stage and angular steel pipes after reshaping the reshaping process A method for manufacturing a steel pipe is characterized in that continuous measurement is carried out online, and the reshaping conditions in the preceding stage from each measurement position are adjusted so that each measurement value is within an allowable limit.

In the second aspect of the present invention, the dimensional accuracy of the round steel pipe is ensured by measuring the shape of the round steel pipe after sizing and adjusting the sizing conditions. Further, the shape of the square steel pipe in the intermediate stage of the reshaping process and after the reshaping is measured, and the relative position adjustment of the reshaping roll is feedback-controlled so that each measured value falls within the allowable limit. The feedback control may be a learning automatic control for learning the relationship between the position of the reshaping roll and the measured value.

[0011] upper Symbol apparatus of the present invention The present invention can be suitably carried out, in the steel pipe production apparatus obtained by adding a square steel pipe manufacturing process tail seam welded steel pipe manufacturing line, circle on the downstream of the sizing roll A steel pipe profile measuring device is arranged, a square steel pipe profile measuring device is arranged in the middle of the reshaping roll group, and a corner shape final shape measuring device of the square steel pipe is arranged on the exit side of the reshaping roll group. Ru an adjustment device in shape to adjust the upstream each roll from each measuring apparatus to be within the allowable value set to each of the measuring device
Together with the round steel pipe profile measuring device and the square steel pipe
Lofeel measuring device is one or more one-dimensional laser distance
Disengager and forward / backward moving mechanism of the laser rangefinder in the distance measuring direction
And rotation to match the optical axis of the laser rangefinder with the measuring direction
The frame and the rotating frame are rotatably supported around them.
The inner frame to be held and the inner frame is surrounded, and the rotation is performed.
Lifting jack that aligns the center of the frame with the center of the square column
An outer frame provided with the steel pipe is provided. This device can be used as a steel pipe manufacturing device for improving the accuracy of a round steel pipe by using it as a transfer device without operating the reshaping roll group.

[0012] Also, the corner final shape measuring device, 1
Alternatively, a plurality of two-dimensional laser rangefinders, a forward / backward moving mechanism of the laser rangefinders in the distance measuring direction, a rotating frame for aligning the optical axis of the laser rangefinders with the measuring direction, and a rotating frame for rotating the rotating frame. Automatic measurement can be easily performed by providing an inner frame that movably supports the periphery and an outer frame that surrounds the inner frame and has an elevating jack that aligns the center of the rotating frame with the center of the corner column. Is preferable.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing a manufacturing process of a steel pipe according to an embodiment of the present invention, showing a sizing roll and subsequent steps in the electric resistance welded steel pipe manufacturing process. The raw pipe weld-formed into a circular cross section is conveyed on the line from the left in the direction of FIG. The element tube is sized with sizing rolls 11 and 12. The round steel pipe profile measuring device 20 for measuring the profile of the round steel pipe after sizing measures the circumferential length, the length / width / diagonal diameter, the roundness, the pass line, and the roll caliber shape of the round steel pipe. Next, the round steel pipe is reshaped into a square steel pipe by reshaping rolls 13, 14, 15, and 16. A square steel pipe profile measuring device 30 is arranged in the middle of the reshaping roll group. The square steel pipe profile measuring device 30 measures the circumferential length, the vertical / horizontal / diagonal diameter, the pass line, the radius of curvature (R value) of the corner portion, and the roll caliber shape of the square steel pipe during the reshaping process. Here, the difference in circumferential length from the measurement value of the round steel pipe profile measuring device 20 (drawing amount), the amount of change in vertical / horizontal / diagonal diameter, and the amount of change in pass line (forming amount) are grasped. The R value of the square steel pipe that has gone out of the reshaping step is measured by the corner shape measuring device 40. The side length, flatness, pass line, circumference,
Vertical, horizontal and diagonal diameters and roll caliber shapes are also measured. Also, the S value can be measured as necessary. The S value refers to the dimension of the corner portion specified in "Table 4 Dimensional tolerance" of JIS G 3466.

FIG. 2 shows a cross section of the pipe in which these measurements are made. FIG. 2 (a) is a cross section of the round steel pipe 50, and FIG.
2B is a cross section of a process of pressing the round steel pipe of FIG. 2A in a flat shape in the vertical and horizontal directions to form the square steel pipe 60, and FIG. 2C is a cross section of the product square steel pipe 70.

The measurement data of the round steel pipe profile measuring device is input to a computer, and the computer measures the round steel pipe 50.
Calculate the circumference, vertical / horizontal / diagonal diameter, roundness, pass line, and roll caliber shape. The calculated data is recorded on the recording medium.

The data digitized by the computer is sent to the process computer. The process computer compares these data with a reference value, outputs a control signal so that the deviation becomes zero, and the sizing rolls 11, 1
Feedback control of the two related positions. The position of the sizing rolls 11 and 12 is adjusted by moving the rolls. Computer sizing rolls 11, 1
The influence of the position adjustment of No. 2 is learned and memorized together with other pipe forming conditions, for example, conditions such as steel pipe size, roll setting accuracy, seam twist, presence or absence of shear cut, material characteristics, deviation of mill center, and roll calvary. After that, the learned data can be used to perform highly accurate control.

A front view of the round steel pipe profile measuring device 20 is shown in FIG. The round steel pipe profile measuring device 20 includes a rotating frame 21, an inner frame 22, and an outer frame 23 that surround the outer circumference of a round steel pipe 50 whose profile is to be measured. The outer frame 23 is formed by assembling the vertical and horizontal frames into a quadrangle, and the inner frame 22 is jacked 24.
And the side surface of the inner frame 22 is supported by four guide rolls. The jack 24 is moved up and down by the height setting motor so that the center of the round steel pipe profile measuring device 20 coincides with the center of the round steel pipe 50.

The inner frame 22 is composed of a horizontal frame and a vertical frame, and is suspended by a jack 24 on an outer frame 23 and moved up and down. The inner frame 22 includes four support rolls, and rotatably supports the outer circumference of the rotating frame 21.

The rotating frame 21 is a circular frame, which is supported by four support rolls 25 on its outer periphery and is rotatable. One or a plurality of laser rangefinders 26 are attached to the rotating frame 21. The laser distance type 26 is attached via a linear way (linear motion mechanism) with its axial center aligned in the radial direction. The linear way moves the laser range finder 26 in the radial direction to adjust the distance between the round steel pipe 50 and the laser range finder 26. The linear way is such that the outer circumference of the round steel pipe 50 falls within the measuring range of the laser distance type 26 according to the size of the round steel pipe 50. Rotating frame 2
1 is rotated by being driven by the servo motor 27. The measurement data of the laser range finder 26 is input to the computer.

Square steel pipe profile measuring device 3 shown in FIG.
0 is configured in the same manner as the round steel pipe profile measuring device 20, and the rotating frame 3 that surrounds the outer periphery of the square steel pipe 60.
1, an inner frame 32 and an outer frame 33 are provided. The outer frame 33 suspends the inner frame 32 with jacks 34, and the side surfaces of the inner frame 32 are supported by four guide rolls. The jack 34 moves up and down the inner frame 32,
The center of the square steel pipe profile measuring device 30 is aligned with the center of the square steel pipe 60.

The rotating frame 31 is a circular frame, which is rotatably supported on the outer periphery by four support rolls 35 and is driven by a servo motor 37 to rotate. One or more laser rangefinders 36 are attached to the rotating frame 31. The linear way moves the laser range finder 36 in the radial direction to adjust the distance between the square steel pipe 60 and the laser range finder 36. The measurement data of the laser range finder 36 is input to the computer.

FIG. 5 is a front view of the corner shape measuring device 40 for a square steel pipe. The square steel pipe corner portion shape measuring device 40 includes a rotating frame 41, an inner frame 42, and an outer frame 43 that surround the outer periphery of the square steel pipe 70 whose profile is to be measured. The outer frame 43 is formed by assembling vertical and horizontal frames into a quadrangle, the inner frame 42 is suspended by a jack 44, and the side surfaces of the inner frame 42 are supported by four guide rolls. The jack 44 is moved up and down by the height setting motor to move the square steel pipe profile measuring device 4
The center of 0 is aligned with the center of the square steel pipe 70. The inner frame 41 consists of a horizontal frame and a vertical frame, and the outer frame 4
3 is suspended by a jack 44 and moves up and down. The inner frame 42 has four support rolls,
The outer periphery of 1 is rotatably supported.

The rotating frame 41 is a circular frame, and the outer periphery thereof is supported by four support rolls 45 so as to be rotatable. Laser rangefinder 4 on rotating frame 41
6 is attached. The laser distance type 46 is mounted via a linear way (linear motion mechanism) with its axial centers aligned in the radial direction. The linear way moves the laser range finder 46 in the radial direction to adjust the distance between the square steel pipe and the laser range finder 46. The linear way is such that the outer circumference of the square steel pipe falls within the measuring range of the laser distance type 46 according to the size of the square steel pipe. The rotating frame 41 is driven by a servo motor 47 to rotate. The measurement data of the laser range finder 46 is input to the computer.

[0024]

EXAMPLE Next, in a line provided with a round steel pipe profile measuring device, a square steel pipe profile measuring device, and a corner shape measuring device according to the present invention, as an example, 250 mm square, plate thickness 6 mm, corner portion Radius of curvature R of 14.5 mm
The square steel pipe was molded, and the roll adjustment was performed by the operator, and the measurement results before and after the roll adjustment were investigated. The transition of measured dimensions before roll adjustment is shown in FIGS. 6 (a), 6 (b) and 6 (c).
FIG. 6A shows a profile of a round steel pipe, FIG. 6B shows a measurement value of a square steel pipe profile measuring device, and FIG. 6C shows a measurement value of a corner shape measuring device. Changes in measured dimensions after roll adjustment are shown in FIGS. 7 (a), (b) and (c). FIG. 7A shows a profile of a round steel pipe, FIG. 7B shows a measurement value of a square steel pipe profile measuring device, and FIG. 7C shows a measurement value of a corner shape measuring device. FIG. 8 schematically shows measurement patterns of the square steel pipe 60 measured by the square steel pipe profile measuring device and the square steel pipe 70 measured by the corner shape measuring device.
The results of these measurements are summarized in Tables 1 and 2.

[0025]

[Table 1]

[0026]

[Table 2]

As is clear from Tables 1 and 2, highly accurate shape control is achieved after the adjustment. Therefore, it is apparent that a square steel pipe with high dimensional accuracy can be obtained by providing the apparatus of the present invention and performing feedback learning control.

Next, FIG. 9 and Table 3 show the measurement results of the examples of round steel pipes. FIG. 9 is a diagram schematically illustrating the shape and figure output of the round steel pipe profile measuring device, and Table 3 shows measured values before and after roll adjustment.

[0029]

[Table 3]

[0030]

The method and apparatus for manufacturing a steel pipe, in which a skelp is formed into an electric resistance welded steel pipe having a circular cross section and then reshaped into a square steel pipe, is constructed as described above. It becomes possible to accurately measure the shape of the square steel pipe by feeding back to the forming process and feeding it back to the forming process, which largely contributes.

[Brief description of drawings]

FIG. 1 is a schematic view showing a manufacturing process of a steel pipe of an example.

FIG. 2 is a sectional view of a steel pipe.

FIG. 3 is a front view of a round steel pipe profile measuring device.

FIG. 4 is a front view of a square steel pipe profile measuring device.

FIG. 5 is a front view of a square steel pipe corner shape measuring device.

FIG. 6 is an explanatory diagram showing the accuracy of a square steel pipe by conventional operator adjustment.

FIG. 7 is an explanatory diagram showing the accuracy of the square steel pipe by the operator adjustment of the embodiment.

FIG. 8 is an explanatory diagram showing an effect of the present invention.

FIG. 9 is an explanatory diagram showing the effect of the present invention.

FIG. 10 is an explanatory view of a hull of an electric resistance welded steel pipe production line.

[Explanation of symbols]

11, 12 sizing rolls 13,14,15,16, Reshaping roll 20 Round steel pipe profile measuring device 21 Rotating frame 22 Inner frame 23 Outer frame 24 jacks 25 Support Roll 26 Laser rangefinder 30 Square Steel Pipe Profile Measuring Device 31 rotating frame 32 inner frame 33 outer frame 34 Jack 35 Support Roll 36 laser rangefinder 40 Corner measurement device 41 Rotating frame 42 Inner frame 43 outer frame 44 jack 45 Support Roll 46 laser rangefinder 100 skelbs 101 molding process 102 welding process 103 Sizing process 104 Cold forming process 105 cutting process 106 square steel pipe

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B21B 17/14 B21B 19/10 B21C 37/00-43/04 B21B 37/00-37/14

Claims (5)

(57) [Claims] 1. When manufacturing a round steel pipe by shaping a skelp into an electric resistance welded steel pipe having a circular cross section and manufacturing the round steel pipe, one or a plurality of one-dimensional laser rangefinders are arranged with their optical axes aligned with the measuring direction. Rotating in the circumferential direction, continuously measuring the profile of the round steel pipe after sizing online, the circumference of the round steel pipe,
Calculates vertical / horizontal / diagonal diameters, roundness, pass lines, roll caliber shapes, and positions of sizing rolls, steel pipe dimensions, roll setting accuracy, seam twist, shear cut so that the calculated values are within allowable limits. A method for manufacturing a steel pipe, characterized by adjusting the presence or absence of the material, the characteristics of the material, the deviation of the mill center, and the pipe making conditions of the roll caliber. Upon be re shaping to 2. A shaped sizing dorsal horn steel pipe Sukerupu the ERW steel pipe having a circular cross section, 1
Or, align the optical axes of multiple one-dimensional laser rangefinders with the measuring direction
The shape of the round steel pipe after sizing is continuously measured online by rotating it in the circumferential direction of the pipe and adjusting the sizing conditions so that the measured value is within the allowable limit, as well as the middle of the reshaping process. Manufacture of a steel pipe characterized by continuously measuring the shape of the square steel pipe after step and after reshaping, and adjusting the reshaping conditions of the preceding stage from each measurement position so that each measured value is within the allowable limit. Method. 3. A steel tube manufacturing apparatus obtained by adding a square steel pipe manufacturing process tail seam welded steel pipe manufacturing line, arranged round steel pipe profile measuring device on the downstream of the sizing roll, the re shaping rolls intermediate A square steel pipe profile measuring device is installed at the corner of the reshaping roll group, and a final shape measuring device at the corner of the square steel pipe is installed at the exit side of the reshaping roll group so that the pipe shape is within the tolerance set for each measuring device. Rutotomoni an adjustment device for adjusting each roll upstream of the measuring device,
The round steel pipe profile measuring device and square steel pipe profiler
The measuring device is one or more one-dimensional laser rangefinders,
A forward / backward moving mechanism of the laser rangefinder in the distance measuring direction;
The rotating frame that aligns the optical axis of the rangefinder with the measuring direction
And the inside that supports the periphery of the rotatable frame in a freely rotatable manner.
The rotating frame that surrounds the frame and the inner frame.
Equipped with a lifting jack that aligns the center with the center of the corner column
An apparatus for manufacturing a steel pipe, comprising: an outer frame . 4. A square steel pipe is manufactured at the tail end of the ERW pipe manufacturing line.
In steel pipe manufacturing equipment with additional processes, the sizing roll
A round steel pipe profile measuring device is installed downstream of the
A square steel pipe profile measuring device is installed in the middle of the
Of the square steel pipe on the exit side of the reshaping roll group.
The corner shape final shape measuring device is installed,
Make sure that each measuring device is within the tolerance set in the measuring device.
With an adjusting device that adjusts each roll upstream,
The corner final shape measuring device is one or a plurality of two-dimensional
Laser rangefinder and front and rear in the direction of distance measurement of the laser rangefinder
Align the advancing mechanism with the optical axis of the laser rangefinder in the measuring direction.
Rotation frame and its circumference so that the rotation frame can rotate freely.
An inner frame for supporting the enclosure, and surrounding the inner frame,
The lifting frame that aligns the center of the rotating frame with the center of the corner column.
And an outer frame having a jack.
Steel pipe manufacturing equipment. 5. The final corner shape measuring device includes one or a plurality of two-dimensional laser rangefinders, a forward / backward moving mechanism of the laser rangefinders in a distance measuring direction, and an optical axis of the laser rangefinders. A rotating frame that matches the measuring direction, an inner frame that rotatably supports the rotating frame, and an elevating jack that surrounds the inner frame and aligns the center of the rotating frame with the center of a square column. apparatus for manufacturing a steel tube according to claim 3 Symbol mounting characterized by comprising an outer frame having.