JP3912185B2 - Steel strip end forming method and forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for forming a steel strip end, and in particular, a steel strip as a material is bent in the width direction to form a circular cross-section, and the butted ends are joined together to form an ERW steel pipe, a pressure welded steel pipe, a forged weld. The present invention relates to a technique for forming a steel strip so that the cross-sectional shape is the same on the left and right of the butting position when manufacturing a steel pipe or the like.
[0002]
[Prior art]
For example, an electric resistance welded steel pipe is generally rolled and formed into a cylindrical shape by a group of forming rolls while a raw steel strip is running, and then welded at the end in the width direction of the abutted steel strip. Manufactured. There are various types of manufacturing and various apparatuses, but an example is shown in FIG.
[0003]
First, a steel slab obtained by continuously casting molten steel is heated to a predetermined temperature in a heating furnace, and then a steel strip having a constant width is formed by hot rolling. And the steel strip 1 which is this raw material is sent into a group of forming rolls 2 at a constant speed with the steel strip surface horizontal. As this forming roll 2, for example, an edge bend roll 3 that bends both ends in the steel strip width direction sequentially from the entry side, a center bend roll 4 that bends the central portion, and an end forming cage A roll 5 and a fin pass roll 6 for finish molding are arranged in series. The steel strip 1 that has been rolled into a cylindrical shape by being hot-rolled by these forming rolls 2 is then heated at its end in the width direction (hereinafter simply referred to as a butted portion or an edge portion) with an induction coil 7 or the like, The tube 9 is formed by pressing with a squeeze roll 8 and crimping and welding. The bead 9 is cut and removed by the bead cutting means 10 in the bead (not shown in the figure, but a spruce formed in a normal welded portion) generated on the inner and outer surfaces of the tube 9. Further, as a heat treatment by the flaw inspection by the ultrasonic flaw detector 11 and an annealing apparatus such as a seam aniler 12, annealing of the welded portion (also referred to as a seam portion) and cooling by the water jet nozzle 13 are sequentially performed. Thereafter, the size is adjusted by a drawing mill 14 such as a stretch reducer or a sizer, and then cut to a desired length by a cutter 15 on a delivery line for dispensing, so that an ERW steel pipe having desired characteristics is obtained. . In addition, after the above-described steps, hot reduction / reduction meat rolling or cold drawing may be performed as necessary. Further, when pressure welding or forge welding is performed instead of the above welding, a pressure welded steel pipe or a forged steel pipe is obtained, which can also be a subject of the present invention.
[0004]
By the way, one of the quality evaluations of a steel pipe manufactured through such a process is that the left and right cross-sectional shapes are the same at a butt portion (also referred to as a seam portion). Otherwise, the appearance of the product is not preferable and the strength is also affected. Therefore, the manufactured steel pipe is finally removed as a rejected product due to a defective shape of the seam portion by observing the cross-sectional shape of the seam portion and not conforming to the criterion. In addition, the ratio which becomes this rejection tends to become so large that the material of a steel strip is a high strength material, or a steel pipe with thin wall thickness.
[0005]
The forming process that has the greatest influence on the left-right symmetrization of the cross-sectional shape is an edge bend roll 3 that begins to bend both ends in the width direction of the steel strip first. Consideration was given as shown in the figure. That is, the lower roll 16 has two substantially coaxial L-shaped surfaces in contact with the steel strip 1 and a relatively wide base, and is arranged on the left and right sides. And left / right movement (the distance between them cannot be changed) are not allowed. That is, only the rotation motor 17 of the lower roll 16 is attached. On the other hand, the upper roll 18 has a shape in which the width of the contact surface with the steel strip 1 is narrow and has a curvature, and the left and right upper rolls 18 are arranged on the same axis and moved up and down in synchronism with each other. Can be moved as a unit. For example, the vertical movement of the upper roll 18 is performed by the vertical movement servo motor 19 through the vertical movement worm jack 25, and the left and right upper rolls 18 are moved by the same amount. Further, the left and right movement of the upper roll 18 is performed by the left and right moving servo motor 20 via the left and right moving screw screw 26, and the left and right upper roll 18 is moved to the left and right by the same amount. Therefore, the left and right upper rolls 18 can move up and down and left and right only by the same amount. Even if the thickness and width of the steel strip 1 are changed, the upper and lower and left and right movement amounts of the upper roll 18 can be set and changed. For example, the end of the steel strip 1 is bent in a state in which left-right symmetry is maintained.
[0006]
However, even if this conventional edge bend roll 3 is used, both ends of the steel strip 1 are not always bent symmetrically, and the right and left cross-sections with the butt portion (also referred to as a seam portion) as a boundary. At present, the problem of having the same shape cannot be completely solved.
[0007]
[Problems to be solved by the invention]
In view of such circumstances, an object of the present invention is to provide a method and an apparatus for forming a steel strip end that can bend both ends in the width direction of the steel strip to the left and right.
[0008]
[Means for Solving the Problems]
The inventor has intensively studied to achieve the above object, and the results have been embodied in the present invention.
[0009]
That is, in the present invention, when the steel strip is squeezed using the edge bend rolls arranged up and down and both ends in the steel strip width direction are bent upward, the vertical movement distance of the upper roll arranged on the left and right and / or Alternatively, a means for individually changing the left and right horizontal positions is provided, the upper rolls arranged on the left and right can be adjusted independently, and the bent shape of the steel strip is always measured, and the measured value is set as a target. Compared with the bent shape, the shape difference is fed back to the means for individually changing the vertical movement distance and / or horizontal position of the upper roll, and the position of the upper roll is adjusted to correct the shape difference. And the bending method of the both ends of this steel strip is left-right symmetric, It is a forming method of the steel strip end part characterized by the above-mentioned.
[0010]
In addition, the present invention is in contact with the upper surface side of the steel strip, is moved in the vertical direction and the left-right direction at the same time, and is in contact with the lower surface side of the steel strip, which has a symmetrical shape. In an edge bend roll having two lower rolls that are symmetrical in shape but are not movable in the vertical direction and the left and right direction, the connecting rod that allows the two upper rolls to move simultaneously is removed, A sensor for measuring the bent shape of the steel strip, provided on the exit side of the upper and lower rolls, and provided with an upper roll moving means that allows the two upper rolls to move independently vertically and horizontally, The measured value is compared with the target bend shape, the shape difference is fed back to the means for individually changing the vertical movement distance and / or horizontal position of the upper roll , the shape difference is corrected, and the steel strip The curved shape at both ends is left The upper end position of the steel strip is adjusted to independently adjust the vertical movement distance and / or the horizontal position of the upper and lower rolls arranged left and right so as to be symmetrical to the right. It is a molding device. In this case, it is preferable that the sensor is a laser rangefinder which is disposed above the traveling steel strip and can move horizontally in the steel strip width direction.
[0011]
ADVANTAGE OF THE INVENTION According to this invention, even if the steel strip to run horizontally meanders to the left or right, or vibrates, it becomes possible to bend the both ends of a steel strip width direction to right and left object. As a result, the acceptance rate of the product is increased and the product yield is improved. In addition, the steel types and size ranges of steel strips that can be used for manufacturing are expanded.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0013]
First, the inventor uses the conventional edge bend roll 3 that, in principle, should be bent symmetrically at both ends in the width direction of the steel strip. The reason why they were not the same was examined. As a result, it was concluded that in actual operation, the traveling steel strip meanders left and right or vibrates and does not travel linearly. Since it is impossible to suppress these meandering and vibrations, the present inventors have completed the present invention by continuously examining separate measures. In other words, the bending shape of the steel strip that has passed through the edge bend roll 3 is always measured, and the measured values are fed back so that the bending shapes at both ends of the steel strip that passes thereafter are symmetrical. The vertical movement distance and / or the horizontal horizontal position of the upper rolls arranged on the left and right are respectively adjusted. Specifically, it is performed by modifying the edge bend roll 3 as follows.
[0014]
As shown in FIG. 3, the conventional edge bend roll 3 is in contact with the upper surface side of the steel strip 1, and can move in the vertical and horizontal directions, and has two symmetrical shapes. The upper roll 18 is provided with two lower rolls 16 that are in contact with the lower surface side of the steel strip 1 and have a bilaterally symmetrical shape but are not movable in the vertical direction and the horizontal direction. Then, the two upper rolls 18 divided on the left and right sides on the same common shaft 28 move in synchronization with each other.
[0015]
Therefore, the order of the two upper rolls 18 to be movable independently in the vertical and horizontal, as shown in Figure 1, remove the connecting rod 27, the servo motor for horizontal movement and vertical movement servo motor 19 a 20a was newly provided. The common shaft 28 of the upper roll 18 is coupled by a joint capable of transmitting rotational power and allowing individual movement of the left and right upper rolls in the vertical direction within an allowable range. Then, on the exit side of the roll along the traveling direction of the steel strip, as shown in FIG. 2, the sensor 21 for measuring the bending shape of the steel strip 1 and the measured value are received, and the bending shapes at both ends of the steel strip are obtained. Upper roll position adjusting means 22 (including an arithmetic unit) for providing a signal for adjusting the vertical movement distance and / or the horizontal horizontal distance of the upper rolls arranged on the left and right sides is provided so as to be symmetrical. Therefore, the measured value obtained by the shear 21 is compared with the target bending shape, and is fed back to the set values of the moving means 19, 19a, 20 and 20a described above to correct the shape difference. The setting value is changed.
[0016]
In this case, the sensor 21 may be of any type as long as the distance can be measured from the upper fixed position of the traveling steel strip 1 toward the lower steel strip 1. In addition, the sensor 21 may be arranged fixedly upward. However, since it is necessary to detect the bent shape of the entire width of the steel strip 1 in a short time, a large number of sensors 21 are required for the fixed type. Therefore, in the present invention, the method of the sensor 21 was also examined, and as shown in FIG. 5, a laser rangefinder that can move horizontally in the steel strip width direction was used. According to this, since the two laser distance meters are attached to the horizontal member 23 so as to be separated from each other, if the horizontal member 23 is moved by half of the width of the steel strip, the steel strip 1 can be formed in a short time. The bending shape of the full width can be measured. Incidentally, if the steel strip width is 400 mm and the horizontal member 23 to which the two sensors 21 are attached is moved at 100 mm / sec, the entire bent shape can be measured in 2 seconds.
[0017]
The above-described position adjustment of the upper roll 18 is all automatically performed via the position adjusting means 22. However, in the present invention, separately, the measurement shape that the operator has shown on the display 24 is used. Monitoring may be performed with a target curve shape line, and the moving means 20 may be remotely operated.
[0018]
【Example】
A steel slab containing C: 0.25% by mass, Si: 0.20% by mass, and Mn: 0.10% by mass was hot-rolled to obtain a steel strip having a width of 455 mm and a wall thickness of 2.0 mm. ERW steel pipe was manufactured from the material. The size of the electric resistance welded steel pipe is an outer diameter of 146 mmφ × wall thickness of 2.0 mm. At that time, the forming apparatus according to the present invention was adopted, and the results of the manufacturing were compared with those manufactured by a conventional edge bend roll. In addition, what was demonstrated in FIG. 4 was utilized as a manufacturing process of an ERW steel pipe.
[0019]
As a result, according to the present invention, the pass rate of the product was improved by 5% because the seam shape was better than before.
[0020]
Next, in order to develop a product corresponding to a high-strength material, as a steel strip material, C: 0.16 mass%, Si: 0.20 mass%, Mn: 2.90 mass%, Cr: 0.12 mass% %, And a steel slab having a tensile strength (Ts) of 850 MPa was hot-rolled to obtain a steel strip having a width of 455 mm and a wall thickness of 2.0 mm, and an ERW steel pipe was manufactured using the steel strip as a raw material. The size of the electric resistance welded steel pipe is an outer diameter of 146 mmφ × thickness of 2.0 mm. Then, the forming apparatus according to the present invention was adopted, and the results of the manufacturing were compared with those manufactured by a conventional edge bend roll. In addition, what was demonstrated in FIG. 4 was utilized as a manufacturing process of an ERW steel pipe.
[0021]
As a result, with the conventional edge bend roll, the seam bending shape was unstable and could not be commercialized. However, according to the present invention, the problem of the seam bending shape was solved, and the product was commercialized with a pass rate of 99%. I was able to achieve it.
[0022]
【The invention's effect】
As described above, according to the present invention, it is possible to bend both ends in the width direction of the steel strip to the left and right sides even if the traveling steel strip meanders horizontally and vibrates. As a result, the acceptance rate of the product is increased and the product yield is improved. In addition, the steel types and size ranges of steel strips that can be used for manufacturing have expanded.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining a steel strip end forming apparatus according to the present invention.
FIG. 2 is a cross-sectional view showing a flow of a steel strip end forming apparatus according to the present invention.
FIG. 3 is a view showing a conventional steel strip end forming apparatus (edge bend roll).
FIG. 4 is a diagram showing a manufacturing process of an electric resistance welded steel pipe embodying the present invention.
FIG. 5 is a diagram schematically showing an example of a sensor employed in the present invention.
[Explanation of symbols]
1 Steel strip 2 Forming roll (group)
3 Edge bend roll 4 Center bend roll 5 Cage roll 6 Fin pass roll 7 Inductive coil 8 Squeeze roll 9 Tubing body 10 Bead cutting means 11 Ultrasonic flaw detector 12 Seam aniller 13 Water injection nozzle 14 Drawing rolling Machine 15 Cutter 16 Lower roll 17 Lower roll rotation motor 18 Upper rolls 19 and 19a Servo motor for moving up and down (moving means)
20 , 20a Servo motor for moving left and right (moving means)
21 Sensor 22 Position adjustment means (including a calculator)
23 Horizontal member 24 Display 25 Warm jack 26 for vertical movement Screw screw for horizontal movement
27 Connecting rod
28 Common axis

Claims (3)

When rolling down the steel strip using the edge bend rolls arranged above and below and bending both ends in the steel strip width direction upward,
Means for individually changing the vertical movement distance and / or horizontal horizontal position of the upper rolls arranged on the left and right are provided, the upper rolls arranged on the left and right can be adjusted independently, and the bending of the steel strip The shape is constantly measured, the measured value is compared with the target bend shape, and the shape difference is fed back to the means for individually changing the vertical movement distance and / or the horizontal position of the upper roll. In order to correct the above, the position of the upper roll is adjusted so that the bent shape of both ends of the steel strip is left-right symmetric. Two upper rolls that are in contact with the upper surface side of the steel strip, move in the vertical and horizontal directions at the same time, and have a symmetrical shape, and a lower surface side of the steel strip. In an edge bend roll with two lower rolls that are not movable in the vertical and horizontal directions,
A connecting rod for simultaneously moving the two upper rolls is removed, and an upper roll moving means is provided to make the two upper rolls movable independently in the vertical and horizontal directions. Compared with the sensor that measures the bending shape of the steel strip and the measurement value is the target bending shape, the vertical movement distance and / or horizontal horizontal position of the upper roll is individually changed. The vertical movement distance and / or the horizontal horizontal position of the upper rolls arranged on the left and right are independently adjusted so that the shape difference is corrected and the bent shape of the steel strip ends is symmetrical. An apparatus for forming an end portion of a steel strip, comprising: an upper roll position adjusting means for adjusting.   3. The steel strip forming apparatus according to claim 2, wherein the sensor is a laser distance meter disposed above the traveling steel strip and horizontally movable in the steel strip width direction.

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