JP3239819B2 - Rolling device and rolling method of rolling mill - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling mill and a rolling method for a rolling mill, and more particularly to a method for transmitting an excessive rolling load to a rolling mill body when an excessive rolling load is applied during rolling. The present invention relates to a rolling mill rolling-down apparatus and a rolling-down method capable of easily repairing equipment when rolling is stopped while the material to be rolled is bitten by abnormal rolling.

[0002]

2. Description of the Related Art A so-called Mannesmann tube method has been widely used as a method for hot-working a seamless steel pipe. In this pipe making method, as shown in FIG. 3, a solid round billet heated to a high temperature is used as a material 1 to be rolled, and the round billet is fed to a piercing mill 4 (a so-called piercer). The shaft core is pierced to obtain a hollow shell. Next, the obtained hollow shell 1 is expanded as it is or through an elongator having the same configuration as that of the above-described piercing and rolling mill to reduce the diameter and thickness, and then sent to a stretching rolling device such as a mandrel rolling mill 5. And stretch-roll. After that, it passes through a stretch reducer 6, a reeler, a sizer, and the like, and passes through a polishing tube, a shape correcting process, and a refinement process of performing sizing.

In such a pipe manufacturing method, a piercing mill 4
, A roll 3b in a mandrel mill 5, a reducer roll 3c in a stretch reducer 6, etc. (hereinafter, "rolling roll" in the present invention)
Collectively. ), The steel pipe is drilled, stretched, polished, and shaped corrected by rolling down the outer peripheral surface of the material 1 to be rolled. Hereinafter, a specific rolling state by a rolling roll during rolling will be described using an example of a mandrel rolling mill.

[0004] As shown in FIG. 3, in a mandrel mill 5, a mandrel 2 is attached to a hollow shell 1 obtained by a piercing mill 4.
The material 1 to be rolled with the mandrel inserted
Through a mandrel mill 5 for elongation rolling. For this reason, the rolling mill is arranged in tandem along a pass line that is in the rolling direction of the material to be rolled 1, and is composed of a plurality of roll stands each having a pair of grooved rolls 3.
Between the adjacent stands, the respective hole-shaped rolls 3 are arranged so as to intersect in a plane perpendicular to the pass line with a rolling direction shifted by 90 °. Then, since the material to be rolled 1 passes through the grooved rolls 3 of each stand with the mandrel 2 inserted, the inner and outer diameters are regulated by the mandrel 2 and the grooved rolls 3 to reduce the inner and outer diameters. Since the mandrel inserted during the mandrel rolling has a fixed size, it is necessary to adjust the reduction amount of the grooved roll 3 for each roll stand in order to manufacture a seamless steel pipe having a predetermined size. For this reason,
In order to efficiently manufacture a steel pipe having a predetermined size with a mandrel rolling mill, a pressing mechanism provided on each of the grooved rolls 3 is important.

Heretofore, as a drafting device used in a rolling mill, a drafting device using an electric screw and a drafting device using a hydraulic servo have been widely used. As shown in FIG. 2 described below, the electric screw screw-down device has a structure in which the electric screw jack 9 rotates the screw screw 10 to move up or down. Of the outer surface of the roll, or a gap is provided between the roller and the rolled material. Therefore, since the pressing device has a relatively simple structure and can be installed at a low manufacturing cost, it is effective as a pressing device for a roll stand that does not always need to control the position of the roller. However, when an abnormal condition occurs during rolling and the rolling load fluctuates, the rolling device cannot directly avoid an excessive rolling load, and the rolling load is directly applied to the rolling mill body. For this reason, adopting such a screw-down device is not effective from the viewpoint of equipment maintenance of main facilities.

[0006] The screw-down device using the hydraulic servo has a feature that it is excellent in high-speed and high-accuracy positioning performance as compared with the electric screw screw-down device. For this reason, a roll stand that has a large rolling load and that always requires the position control of the hole-type roll, in other words, a roll stand that requires a high output and responsiveness requires a hydraulic servo to reduce the roll. Is effective. In addition, when an abnormality occurs during rolling and the rolling load fluctuates, the rolling device can absorb the fluctuation of the rolling load by a hydraulic mechanism. However, in the hydraulic servo system, the stroke of the servo cylinder cannot be made large to secure the response of the servo, and is generally 100 mm or less. Under these conditions, when the material to be rolled is bitten into the rolling mill by abnormal rolling and the rolling is stopped, it is difficult to release the grooved roll having bitten, and It takes a long time to remove the rolled material. When such a situation occurs, the rolling efficiency is significantly reduced. Furthermore, the long time required for the abnormal rolling process not only reduces the efficiency of the mandrel rolling mill, but also in particular, as in recent years, the continuous use of Mannesmann pipe making equipment for the purpose of high-efficiency production of seamless steel pipes. Once implemented, the overall efficiency of seamless steel pipe production will be impaired.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the problem of abnormal rolling of a rolling mill widely used as a Mannesmann pipe manufacturing method for seamless steel pipes, and has been developed in the event that an excessive rolling load is applied. Even in the middle, the fluctuation of the rolling load can be absorbed, and furthermore, with the occurrence of abnormal rolling, even if the rolling stops while biting the material to be rolled, the roll opening of the rolling mill can be easily expanded. In addition, the present invention provides a rolling mill rolling-down device and a rolling-down method capable of taking out a biting material to be rolled and repairing the equipment.

[0008]

The gist of the present invention is, as shown in FIG. 1, the following (1) a rolling mill reduction apparatus and (2) a rolling reduction method using the same.

(1) A rolling device 8 for applying a rolling force to a material 1 to be rolled through a rolling roll 3 during rolling.
Are provided with a hydraulic cylinder 11 and a hydraulic cylinder rod 12 enclosing the same, and a screw down screw 10 rotated by an electric screw jack 9. The hydraulic cylinder 11 is attached to a rolling mill stand 7, and the hydraulic cylinder rod 12 stops rotating. Is provided, and on the inner surface, a female screw surface to be screwed with a male screw surface machined on the outer surface of the screw down screw is provided. With the rotation of the screw down screw 10, the rolling roll 3 held at the tip rises. It is a rolling-down device of a rolling mill characterized by descending.

(2) A rolling method using the rolling device according to the above (1), wherein during rolling, the rolling roll is lowered by rotating the rolling screw in a descending direction and an excessive rolling load is sealed in a hydraulic cylinder. A method for rolling down a rolling mill, characterized in that the hydraulic cylinder is retracted during abnormal rolling, the hydraulic cylinder is retracted, and a gap is immediately provided between a material to be rolled and a rolling roll.

In the present invention, as described above, the term "rolling roll" is used as a general term for a piercing roll in a piercing mill applied in the Mannesmann pipe manufacturing method, a grooved roll in a mandrel rolling mill, a reducer roll in a stretch reducer, and the like.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The rolling device for a rolling mill according to the present invention is provided with a hydraulic cylinder and a hydraulic cylinder rod filled with hydraulic oil, and a pressing screw rotated by an electric screw jack. Is provided with a rotation stop, and the inner surface is provided with a female screw surface to be screwed with a male screw surface machined on the outer surface of the screw, so that the rolling roll is raised and lowered with the rotation of the screw. It is characterized by:

Therefore, the rolling method according to the present invention, which is used in such a rolling device of a rolling mill, reduces the rolling roll by rotating the rolling screw during the rolling and absorbs an excessive rolling load by the hydraulic cylinder. During rolling, the hydraulic cylinder is retracted and a gap is immediately provided between the material to be rolled and the rolling roll.

Since the rolling device and the rolling method of the rolling mill according to the present invention have the above-mentioned features, when an abnormality occurs during rolling and the rolling load fluctuates, the relief valve of the hydraulic device is adjusted immediately. Since an excessive rolling load can be avoided, it is possible to prevent the rolling load from being directly applied to the rolling mill main body, and to prevent the reduction system from being damaged. Furthermore, by abnormal rolling, the material to be rolled is bitten into the inside of the rolling mill, and even when the rolling is stopped, by retracting the hydraulic cylinder, the grooved roll and the material to be rolled are caught. Since a gap can be provided between the members, the material to be rolled can be taken out immediately.

Further, the device configuration of the screw-down device according to the present invention mainly comprises a combination of a screw-down mechanism using an electric screw and a screw-down mechanism using a hydraulic system. Therefore, not only the predetermined controllability is exhibited, but also the apparatus configuration is simple and excellent in maintainability, and the installation cost of the apparatus is low.

Hereinafter, the effects of the present invention will be specifically described with reference to examples. However, the following disclosure is merely an example of the present invention, and does not limit the technical scope of the present invention.

[0017]

FIG. 1 is a front sectional view for explaining the entire structure of a rolling device of a rolling mill according to the present invention, and is a view showing a configuration of an upper left quarter of a grooved roll rolling device in a mandrel rolling machine. The screw-down device 8 is provided at its tip with a screw 10 for holding the roll 3 so as to penetrate the device up and down. An electric screw jack 9 is provided on the upper part of the screw 10. The screw 10 is rotated by the driving of the electric screw 9, and as shown in FIG. Roll 3 moves up or down. On the other hand, a hydraulic cylinder 11 and a hydraulic cylinder rod 12 are provided so as to surround the outer periphery of the screw 10, and a hydraulic oil 13 is sealed between them. Furthermore, the hydraulic cylinder 11
It is fixed to the rolling mill stand 7 by the mounting device 14. As described above, the object of the present invention can be achieved by developing a screw-down device that combines a screw-down mechanism using an electric screw and a hydraulic mechanism in which hydraulic oil is sealed.

FIG. 2 is a partial sectional view of a main part for explaining a detailed mechanism of a rolling-down device of a rolling mill according to the present invention. In the figure, a hole type roll is attached to the tip of the screw down screw 10 on the left side of the drawing, but illustration is omitted. A drive source for rotating the screw down screw 10 is an electric screw jack 9 provided on the upper end side, and rotates the screw down screw 10 via a long key 10a. A male screw surface 10b is formed on the outer peripheral surface of the middle portion of the screw down screw 10. On the other hand, a hydraulic cylinder 11 containing hydraulic oil 13 and a hydraulic cylinder rod 12 are arranged so as to surround the screw 10. The hydraulic cylinder 11 is fixed to the rolling mill stand 7 by a mounting device 14.
A female screw surface 12b is provided on the inner peripheral surface of the hydraulic cylinder rod 12, and is screwed with the male screw surface 10b of the screw down screw 10. But the hydraulic cylinder rod 12
Is provided with an anti-rotation mechanism 12a at the end thereof, and the rotation of the hydraulic cylinder rod 12 is restrained.
There is no co-rotation. For this reason, the screw 10
When the rotational drive is applied to the hydraulic cylinder rod 12, the screw down screw 10 moves up or down with reference to the hydraulic cylinder rod 12 whose rotation is restricted.

In the case of using the drafting device having the above-described configuration, it is necessary to determine the drafting position of the roller in a state where the hydraulic oil is sealed in the hydraulic cylinder. As described above, the material to be rolled is reduced with the working oil in the hydraulic cylinder interposed therebetween, so that the rolling load is always transmitted to the rolling mill body during rolling through the hydraulic cylinder.
That is, as shown in FIG. 2, the rolling load from the material to be rolled follows the path of the grooved roll → the screw 10 → the hydraulic cylinder rod 12 → the hydraulic cylinder 11 → the mounting device 14 → the rolling mill stand 7 It is transmitted to the main body.

Therefore, if a relief valve is provided in the hydraulic cylinder device so as to absorb the abnormal pressure, even if an abnormality occurs during rolling and the rolling load fluctuates, an excessively large rolling load is immediately obtained. Can be avoided. Further, due to abnormal rolling, the material to be rolled is caught in the inside of the rolling mill, and even when the rolling is stopped, by retracting the hydraulic cylinder, the material of the grooved roll and the material to be rolled are caught. A gap can be provided between them.
Therefore, the rolled material can be easily taken out, and the abnormal situation can be quickly recovered.

[0021] As described above, the present invention relates to a rolling mill rolling device that exhibits excellent equipment protection against fluctuations in rolling load in a Mannesmann pipe and quick repairability of equipment against a stop caused by abnormal rolling. This is the rolling method used for this.

[0022]

According to the rolling device and the rolling method of the rolling mill of the present invention, when an excessive rolling load is applied, the fluctuation of the rolling load can be absorbed even during rolling, and the abnormal rolling may occur. Therefore, even if the rolling is stopped while the material to be rolled is engaged, the equipment of the rolling mill can be easily repaired. Moreover, these can be realized with low capital investment. In addition, as a highly efficient production of seamless steel pipes, it can help to implement continuous Mannesmann pipe making equipment.

[Brief description of the drawings]

FIG. 1 is a front cross-sectional view illustrating an entire configuration of a rolling device of a rolling mill according to the present invention, and is a diagram illustrating a configuration of an upper left quarter of a grooved roll rolling device in a mandrel rolling mill.

FIG. 2 is a partial cross-sectional view of a main part illustrating a detailed mechanism of a rolling device of a rolling mill according to the present invention.

FIG. 3 is a diagram illustrating a Mannesmann pipe manufacturing method which is a method of manufacturing a seamless steel pipe by hot working.

[Explanation of symbols]

 1: Material to be rolled, 2: Mandrel 3: Rolling roll, grooved roll, etc. 4: Punch rolling mill 5: Mandrel rolling machine 6: Stretch reducer 7: Rolling mill stand 8: Rolling-down device 9: Electric screw jack 10: Rolling-down screw 11: Hydraulic cylinder 12: Hydraulic cylinder rod 13: Hydraulic oil, 14: Mounting device

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-185123 (JP, A) JP-A-64-18509 (JP, A) JP-A-7-80515 (JP, A) 122702 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B21B 31/32 B21B 19/04 B21B 31/24

Claims (2)

(57) [Claims] 1. A reduction device for applying a reduction force to a material to be rolled through a rolling roll during rolling, comprising a hydraulic cylinder and a hydraulic cylinder rod filled with hydraulic oil, and a reduction screw rotated by an electric screw jack. The hydraulic cylinder is mounted on a rolling mill stand, the hydraulic cylinder rod is provided with a rotation stop, and an inner surface is provided with a female screw surface to be screwed with a male screw surface machined on the outer surface of the screw down screw. A rolling device for a rolling mill, wherein a rolling roll held at a tip thereof rises and falls with rotation of a rolling screw. 2. A rolling method using a rolling device according to claim 1, wherein during rolling, the rolling roll is lowered by rotation of a rolling screw in a descending direction and an excessive rolling load is enclosed in a hydraulic cylinder. A method for rolling down a rolling mill, comprising absorbing oil and causing the hydraulic cylinder to retract during abnormal rolling to immediately provide a gap between a material to be rolled and a rolling roll.