JP4123549B2 - Mandrel emergency drawing device and mandrel mill using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mandrel drawing device and a mandrel mill using the mandrel drawing device, and more particularly, to a mandrel drawing device corresponding to an emergency drawing of a mandrel accompanying test rolling or misoperation rolling and a mandrel mill including the mandrel drawing device.
[0002]
[Prior art]
As a method of manufacturing a seamless steel pipe hot, a pipe manufacturing method using a mandrel mill is widely adopted as a so-called Mannesmann pipe. In this pipe making method, a solid round billet heated to a high temperature is drilled with a piercer to obtain a hollow shell, and then a mandrel (mandrel bar) is inserted into the hollow shell and the mandrel is inserted. This is performed by rolling the hollow shell in a state of passing through a mandrel mill. This mandrel mill is a rolling facility in which a plurality of rolling roll stands equipped with caliber rolls are arranged in tandem, and the hollow core tube is controlled by its mandrel, caliber roll and inner and outer diameters while passing through the rolling facility. Is reduced and drawn to a predetermined dimension to produce a seamless steel pipe.
[0003]
The pipe making method using a mandrel mill is classified into three methods according to the restraint state of the mandrel during rolling. First of all, the full floating mandrel mill method is a method in which the mandrel inserted into the hollow shell moves together with the rolled tube without any restraint, and the relative speed of the mandrel with respect to the hollow shell varies, so that the longitudinal direction of the steel pipe is changed. Uneven thickness is likely to occur. The following semi-floating mandrel mill method is a rolling method in which the mandrel is restrained in the longitudinal direction of the steel pipe by restraining the rear end of the mandrel so that the mandrel is moved to the progress of the hollow shell during rolling. The dimensional accuracy can be increased. Both of the above-mentioned two methods are transported to the exit side of the mandrel mill while the mandrel is fitted to the rolling tube after rolling, and the mandrel is extracted from the rolling tube using a stripper device in the subsequent process. It may be difficult to pull out or the inner surface quality may deteriorate. In order to solve such problems, a retract mandrel mill method was developed.
[0004]
FIG. 3 is a diagram schematically illustrating the configuration and rolling condition of the entrance-side rolling equipment in the retract mandrel mill method. The entry side of the mandrel mill 3 includes an entry side table 4 for inserting the mandrel 1 through the hollow shell 2 and a mandrel holding device 5 (a retainer). On the other hand, although not shown, an extractor composed of a plurality of pinch rolls is continuously arranged on the exit side of the mandrel 3. As a pre-stage of mandrel mill rolling, the hollow shell 2 and the mandrel 1 are individually conveyed to the entry side table 4. The hollow shell 2 pierced by a piercer or the like is conveyed to a raw tube roller 4a provided on the downstream side of the entry table 4, whereas the mandrel 1 lubricated on the outer surface of the entry table 4 is similarly provided. It is transferred to and held by the mandrel roller 4b provided on the upstream side.
[0005]
The mandrel 1 held by the mandrel roller 4b is sandwiched at its rear end by the mandrel holding device 5. Next, the mandrel 1 on the mandrel roller 4b is fed into the hollow part of the hollow tube 2 stopped on the tube 4a, and the mandrel 1 is inserted into the hollow tube 2 and then passed through the mandrel mill 3 as it is. Rolled. At this time, the rear end portion of the mandrel 1 is restrained by the mandrel holding device 5, and the movement amount of the mandrel 1 is controlled while the hollow shell 2 is being rolled. Simultaneously with the end of rolling, the mandrel 1 is stopped and restrained by the mandrel holding device 5, and the mandrel 1 is separated from the rolling tube by pulling out the rolling tube by the extractor. Then, the mandrel 1 pulled out from the rolled material after the end of rolling is retracted by the mandrel holding device 5 and moved to the entry side of the mandrel mill 3.
[0006]
In order to analyze the rolling phenomenon, there is a case where the rolling is interrupted during the mandrel mill rolling, or misrolling may occur due to poor lubrication of the mandrel surface. That is, since the continuous rolling by the multi-stands of the hollow shell 3 inserted through the mandrel 1 by the mandrel mill is unsatisfactory, the rolling has to be stopped while the hollow shell 2 is engaged with the mandrel 1 during the rolling. In such a case, the mandrel and the hollow shell must be separated urgently. Therefore, as shown in FIG. 3, a mandrel pulling device 6 for pulling out the mandrel 1 is provided between the raw tube roll 4 a and the mandrel roll 4 b of the inlet table 4. Also, in the conventional mandrel pulling apparatus, a method of attaching a U-shaped guide is often used.
[0007]
FIG. 4 is a perspective view for explaining the configuration of a conventional mandrel pulling apparatus for attaching a U-shaped guide. The mandrel extraction device 6 has a U-shaped guide 7 mounted on a guide body 8 and is tiltable by a cylinder mechanism (not shown), and is tilted so as not to interfere with the conveyance of the mandrel and the hollow shell during normal rolling. The The groove width D of the U-shaped groove formed in the U-shaped guide is larger than the mandrel diameter but smaller than the outer diameter of the hollow shell. When an abnormal situation occurs during rolling, the mandrel extraction device 6 is immediately started up, and the mandrel held by the mandrel holding device is retracted in the U-shaped guide. At this time, the mandrel passes through the U-shaped groove of the U-shaped guide, but only the hollow shell is restrained from retreating in the axial direction by the U-shaped groove, so that the mandrel and the hollow shell are separated.
[0008]
As described above, when an abnormal situation occurs during rolling, it is necessary to immediately extract the mandrel, and therefore, a U-shaped guide that forms a groove width corresponding to the mandrel diameter must always be attached to the drawing device. . On the other hand, in order to pull out the mandrel from the hollow hollow tube, the gap between the U-shaped groove width of the U-shaped guide, the mandrel diameter, and the outer diameter of the hollow hollow tube must be maintained within a certain range. For this reason, when the mandrel is replaced by the pipe making step change, it is necessary to replace the U-shaped guide each time.
[0009]
However, the replacement of the U-shaped guide in the conventional mandrel mill has been performed manually by providing a portal crane or placing a jig crane on the rolling entry side. Such a manual replacement operation requires a large number of man-hours, and this causes a reduction in the operating rate of the mandrel mill. In particular, as in recent years, when Mannesmann pipe production facilities are being continued for the purpose of high-efficiency production of seamless steel pipes, the replacement of U-shaped guides will reduce the overall efficiency of seamless steel pipe production. Can also be.
[0010]
[Problems to be solved by the invention]
In consideration of the problem of replacing the U-shaped guide attached to the mandrel drawing device of the conventional mandrel mill, the present invention is provided with a U-shaped guide group for forming a plurality of U-shaped grooves. A mandrel pulling apparatus that can automate selection and switching, eliminates the need to replace the U-shaped guide every time the pipe making is changed, and supports small-lot, high-mix production of seamless steel pipes from small diameters to large diameters. The aim is to provide a mandrel mill.
[0011]
[Means for Solving the Problems]
The gist of the present invention resides in a mandrel emergency drawing apparatus (1) below and a mandrel mill using the mandrel (2) below.
[0012]
(1) U that forms a groove width that is larger than the mandrel diameter but smaller than the outer diameter of the hollow shell so that the axial movement of the hollow shell inserted through the mandrel is restricted and the mandrel 1 is pulled out of the hollow shell. shaped guide 7 is mounted, Oite the extracting device 6 of the mandrel with a guide body 8 which is tiltably supported by the tilt shaft 12, a U-shaped guide group 7 forming two or more groove width, U-shaped guide comprises a means 9, 10 to select and switch the U-shaped guide 7 to form a groove width corresponding to the mandrel diameter from among the group, these components, a manual stage tilting the entire apparatus from the member, In this tilting means, the guide body 8 is tilted and supported in the mandrel traveling direction via the tilting shaft so as not to hinder the movement of the mandrel during normal rolling, and the U-shaped guide 7 is supported by the mandrel during abnormal rolling. And characterized in that the guide body 8 as the mandrel 1 from the hollow shell to restrain axial movement of the inserted hollow shell is pulled out are arranged tilting cylinder 11 to launch through said tilting axis mandrel emergency drawing device that (see FIG. 1).
[0013]
(2) In a mandrel mill 3 for drawing and rolling the hollow shell 2 in a state where the mandrel 1 is inserted, an apparatus 4 for inserting the mandrel into the hollow shell on the rolling entry side, and a rear end of the mandrel while being rolled by the mandrel mill And a mandrel holding device 5 for retracting the mandrel after rolling or when necessary, and a mandrel emergency drawing device 6 described in (1) above (see FIG. 3).
[0014]
In the above (2), the device for inserting the mandrel into the hollow shell is a tube 4a provided on the entrance table 4 that stops and holds the hollow shell 2, and the mandrel 1 is a hollow portion of the hollow shell 2. It is comprised with the roller 4b for mandrels provided in the entrance side table 4 sent in toward. Further, the mandrel holding device 5 has a structure capable of moving forward and backward by a driving roll.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
The mandrel pulling device of the present invention has a U-shaped guide that pulls out the mandrel while restricting the axial movement of the hollow shell, and has a simple structure. In addition, a U-shaped guide group that forms a groove width of a U-shaped groove corresponding to all of the mandrels held by the mandrel mill is provided, and an appropriate U-shaped guide is selected from the U-shaped guide group. And switching means and means for tilting the entire apparatus. For this reason, even if it is a case where rolling abnormality generate | occur | produces, a mandrel can be reliably extracted from the hollow element tube of the biting state. Moreover, the replacement of the U-shaped guide can be automated without relying on manual work.
[0016]
In the mandrel of the present invention using such a mandrel pulling device, it is not necessary to replace the U-shaped guide attached to the mandrel pulling device every time the pipe making is changed, so that the efficiency of the setting change can be improved and the small diameter of the pipe making size can be achieved. It is the most suitable to cope with small-lot and multi-product production of seamless steel pipes from large to large diameter.
[0017]
Hereinafter, the content of the present invention will be described based on specific examples. However, this disclosure is only an example of the present invention, and the mandrel drawing device and the mandrel mill of the present invention are not limited thereto. Is as described above.
[0018]
【Example】
1A and 1B are diagrams for explaining a configuration example of a mandrel pulling apparatus according to the present invention. FIG. 1A shows a front configuration, and FIG. 1B shows a plan configuration. The mandrel pulling device 6 basically includes a U-shaped guide 7 and a guide body 8 that supports the U-shaped guide 7. Since the U-shaped guide 7 constitutes a U-shaped guide group that forms a groove width of two or more types of U-shaped grooves, the U-shaped guide 7 is pivotally supported by the guide main body 8 by a guide rotating shaft 9. By adopting such a structure, selection / switching of the U-shaped guide 7 is performed by turning the guide rotating shaft 9 and sequentially switching the U-shaped guide. In this embodiment, the rotation of the guide rotating shaft 9 is performed by the action of a pinion attached to the tip of the guide rotating shaft 9 and a rack built in the rotating cylinder 10.
[0019]
FIG. 2 is a diagram schematically illustrating a method of switching a U-shaped guide attached to the mandrel extraction device. As is apparent from the figure, the U-shaped guide 7 is formed with four U-shaped grooves so as to correspond to four types of mandrel diameters, and these constitute a set of U-shaped guide groups. In order to select and switch the optimum U-shaped guide 7 from the U-shaped guide group, the U-shaped guide 7 is turned in the direction of the arrow in the figure. As described above, the turning of the U-shaped guide 7 is based on the combination of the pinion 9p attached to the tip of the guide rotating shaft 9 and the rack 10r operated by the rotating cylinder 10. That is, the rack 10r is displaced by supplying a driving fluid into the rotating cylinder 10, and the pinion 9p is turned according to the displacement, and the optimum U-shaped guide 7 is selected. Since the turning direction of the U-shaped guide 7 can be easily adjusted by changing the operating direction of the rotating cylinder 10, the selection and switching of the U-shaped guide can be easily performed.
[0020]
As indicated by a broken line in FIG. 1, the height at which the mandrel 1 is transported needs to be at a position where it interferes with the U-shaped guide 7 and the guide body 8 of the mandrel extraction device 6. However, since the mandrel 1 and the hollow shell 2 cannot be conveyed during normal rolling, the tilting cylinder 11 is provided, and the entire drawing device is tilted forward about the tilting shaft 12.
[0021]
When rolling abnormalities such as the above-mentioned halfway stop or mis-rolling occur during mandrel mill rolling, the tilting cylinder 11 is immediately actuated to start up the mandrel drawing device 6. Thereafter, when the mandrel 1 clamped by the mandrel holding device is retracted in the U-shaped guide 7 in a state where the mandrel 1 is caught in the hollow shell 2, the mandrel 1 is attached to the U-shaped guide 7 as shown in FIG. Although it can pass through the U-shaped groove, the tube end portion of the hollow shell 2 is restrained from retreating by the U-shaped guide 7, and the mandrel 1 is pulled out from the hollow shell 2. Usually, when the mandrel 1 is pulled out, a load of several hundreds of T is applied to the mandrel pulling device 6, but there is no problem of deformation or bending of the mandrel pulling device 6 by fixing and supporting the guide body 8 with the guide bed 13.
[0022]
【The invention's effect】
According to the mandrel drawing device and the mandrel mill of the present invention, the switching of the U-shaped guide is automated, the U-shaped guide is not replaced every time the pipe making is changed, and a small amount of seamless steel pipes ranging from a small diameter to a large diameter are produced. Applicable to variety production.
[Brief description of the drawings]
FIGS. 1A and 1B are diagrams illustrating a configuration example of a mandrel extraction device of the present invention, in which FIG. 1A shows a front configuration and FIG. 1B shows a plan configuration.
FIG. 2 is a diagram schematically illustrating a method for switching a U-shaped guide attached to a mandrel pulling device.
FIG. 3 is a diagram schematically illustrating the configuration and rolling condition of an entrance-side rolling facility in the retract mandrel mill method.
FIG. 4 is a perspective view for explaining the configuration of a conventional mandrel pulling apparatus with a U-shaped guide.
[Explanation of symbols]
1: mandrel, 2: hollow shell 3: mandrel mill 4: entry side table
4a, 4b: Roller for mandrel, mandrel roller 5: mandrel holding device 6: mandrel pulling device 7: U-shaped guide, 8: guide body 9: guide rotating shaft
10: Rotating cylinder
11: Tilt cylinder, 12: Tilt axis
13: Guide bet

Claims (2)

As pulled out mandrel from the hollow shell to restrain axial movement of the hollow shell that is inserted into a mandrel, mounting the U-shaped guide which forms a smaller groove width than the outer diameter of the hollow shell is larger than the mandrel diameter and, Oite the extracting device of a mandrel having a guide body supported on tiltably tilting axis,
A U-shaped guide group that forms two or more groove widths;
Means for selecting / switching a U-shaped guide forming a groove width corresponding to the mandrel diameter from the U-shaped guide group;
And a means for tilting the entire apparatus composed of these parts and members,
In this tilting means, the guide body is tilted and supported through the tilting shaft in the mandrel traveling direction so as not to hinder the movement of the mandrel during normal rolling, and the U-shaped guide is inserted through the mandrel during abnormal rolling. A mandrel emergency pulling device, characterized in that a tilting cylinder is arranged to raise the guide body through the tilting shaft so that the mandrel is pulled out of the hollow shell while restraining the movement of the tube in the axial direction . In a mandrel mill that stretches and rolls a hollow shell in a state where the mandrel is inserted,
A device for inserting a mandrel through a hollow shell at the rolling entry side;
A mandrel holding device that restrains the rear end of the mandrel while being rolled by the mandrel mill, and retracts the mandrel after completion of rolling or when necessary,
A mandrel mill comprising the mandrel emergency drawing device according to claim 1.

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