JP4428418B2 - Mandrel emergency drawing device, mandrel emergency drawing method, and mandrel mill using the same - Google Patents

Description

  The present invention relates to a mandrel emergency drawing device and a mandrel emergency drawing method, and a mandrel mill using these, and more specifically, a mandrel emergency drawing device and a mandrel emergency drawing method corresponding to an emergency drawing of a mandrel accompanying test rolling or misoperation rolling, In addition, the present invention relates to a mandrel mill using these.

  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.

  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.

  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, while the mandrel 1 lubricated and applied to the outer surface of the entrance table 4 is similarly provided. It is transferred to and held by the mandrel roller 4b provided on the upstream side.

  The mandrel 1 held by the mandrel roller 4 b 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 portion of the hollow shell 2 stopped on the raw tube roller 4a, and the mandrel 1 is inserted into the hollow shell 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.

  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.

  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.

  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.

  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.

  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.

  The gist of the present invention resides in a mandrel emergency drawing device (1) and a mandrel emergency drawing method (2) and a mandrel mill using these (3).

(1) A U-shaped guide group 7 that forms two or more types of groove widths that are larger than the mandrel diameter but smaller than the outer diameter of the hollow shell 2, and a groove width corresponding to the mandrel diameter is selected from the U-shaped guide 7 group. Means 9 and 10 for selecting / switching the U-shaped guide 7 to be formed, a guide body 8 equipped with the U-shaped guide 7 and having the U-shaped guide selecting / switching means, and the guide body can be tilted. The guide body 8 includes a tilting shaft 12 to be supported and a guide bed 13 for restricting the movement of the guide body 8 in the mandrel pulling direction, and further prevents the movement of the mandrel 1 during normal rolling. The U-shaped guide 8 restrains the movement of the hollow tube 2 inserted through the mandrel 1 in the axial direction during the abnormal rolling, and the mandrel is moved from the hollow tube 2 to the mandrel. Barrel 1 mandrel emergency withdrawing apparatus, wherein a disposing said guide body 8 the guide tilting cylinder 11 the bet 13 to a position in contact causes through the tilting shaft so pulled out (see Fig. 1).

(2) Two or more groove widths larger than the mandrel diameter but smaller than the outer diameter of the hollow shell so that the hollow shell inserted through the mandrel is restrained from moving in the axial direction and pulled out of the hollow shell. A U-shaped guide group to be formed is mounted on the guide body, and a U-shaped guide that forms a groove width corresponding to the mandrel diameter is selected from the U-shaped guide group and switched to the selected U-shaped guide. The guide body is tilted and supported in the mandrel traveling direction so as not to hinder the movement of the mandrel during normal rolling. At the same time, the guide body is supported by the guide bed that causes the guide body and restrains the movement in the mandrel traveling direction during abnormal rolling. The U-shaped guide restrains the movement of the hollow shell inserted through the mandrel and pulls out the mandrel from the hollow shell. Rumandoreru emergency pull-out method.

(3) In a mandrel mill 3 for drawing and rolling the hollow shell 2 in a state where the mandrel 1 is inserted, a device 4 for inserting the mandrel into the hollow shell on the rolling entry side, and the 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).

  The mandrel mill of the above (3) is characterized by further restricting the movement of the hollow shell inserted through the mandrel and pulling out the mandrel from the hollow shell by the mandrel emergency pulling method described in the above (2) during abnormal rolling. .

  In the above (3), the device for inserting the mandrel into the hollow shell is a tube 4a provided on the entry side table 4 for stopping and holding the hollow tube 2, and the mandrel 1 in the 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.

  According to the mandrel emergency drawing apparatus and the mandrel emergency drawing method of the present invention, the mandrel and the hollow shell can be reliably separated at the time of abnormal rolling without causing any trouble in the transportation of the mandrel and the hollow shell during normal rolling. When the setup is changed, the switching of the U-shaped guide can be automated, and the U-shaped guide replacement for every pipe-making setup change can be eliminated. The mandrel mill of the present invention using these can appropriately cope with small-scale and multi-product production of seamless steel pipes ranging from a small diameter to a large diameter of the pipe making dimensions.

  The mandrel pulling emergency device and mandrel pulling emergency method of the present invention has a U-shaped guide that pulls out the mandrel while restraining the movement of the hollow shell in the axial direction, 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, in the mandrel pulling emergency device and mandrel pulling emergency method of the present invention, the mandrel can be reliably pulled out from the hollow hollow tube in a bitten state even when a rolling abnormality occurs. Moreover, the replacement of the U-shaped guide can be automated without relying on manual work.

  In the mandrel of the present invention using such a mandrel pulling emergency device and mandrel pulling emergency method, it is not necessary to replace the U-shaped guide attached to the mandrel pulling device every time the pipe making is changed. This is optimal for small-lot, multi-product production of seamless steel pipes with small to large diameters.

  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.

  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 turning 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.

  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 end 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 amount, 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.

  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.

  When a rolling abnormality such as the above-mentioned halfway stop or mis-rolling occurs 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, 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 are no problems such as deformation and bending of the mandrel pulling device 6 by fixing and supporting the guide body 8 with the guide bed 13.

  According to the mandrel emergency drawing apparatus and the mandrel emergency drawing method of the present invention, the mandrel and the hollow shell can be reliably separated at the time of abnormal rolling without causing any trouble in the transportation of the mandrel and the hollow shell during normal rolling. When the setup is changed, the switching of the U-shaped guide can be automated, and the U-shaped guide replacement for every pipe-making setup change can be eliminated. The mandrel mill of the present invention using these can appropriately be used as a rolling method for seamless steel pipes because it can appropriately cope with small-scale and multi-product production of seamless steel pipes from small diameters to large diameters.

It is a figure explaining the structural example of the mandrel drawing-out apparatus of this invention, The same figure (a) has shown the front structure, (b) has each shown the plane structure. It is a figure which illustrates typically the switching method of the U-shaped guide with which a mandrel extraction apparatus is mounted | worn. It is a figure which illustrates typically the composition and rolling condition of the entrance side rolling equipment in a retract mandrel mill method. It is a perspective view explaining the structure of the mandrel pulling-out apparatus of the type | system | group which mounts the conventional U-shaped guide.

Explanation of symbols

1: mandrel, 2: hollow core tube 3: mandrel mill, 4: entry side table 4a, 4b: base tube, mandrel roller 5: mandrel holding device 6: mandrel pulling device 7: U-shaped guide, 8: guide body 9 : Guide rotating body, 10: Rotating cylinder 11: Inclined cylinder, 12: Inclined shaft 13: Guide head

Claims (4)

A U-shaped guide group that forms two or more groove widths larger than the mandrel diameter but smaller than the outer diameter of the hollow shell;
Means for selecting / switching a U-shaped guide that forms a groove width corresponding to the mandrel diameter from the U-shaped guide group;
A guide main body equipped with the U-shaped guide and provided with the U-shaped guide selection / switching means;
A tilting shaft that supports the guide body in a tiltable manner;
A guide bed for restraining movement of the guide body in the mandrel extraction direction;
Further, during normal rolling, the guide body is tilted and supported via the tilting shaft in the mandrel traveling direction so as not to hinder the movement of the mandrel, and during abnormal rolling, the U-shaped guide is moved through the mandrel. A mandrel emergency pulling device is provided, in which a tilting cylinder is provided that causes the guide main body to be brought into contact with the guide bed through the tilting shaft so that the mandrel is pulled out from the hollow shell. U and 2 which form two or more groove widths larger than the mandrel diameter but smaller than the outer diameter of the hollow shell so that the hollow shell inserted through the mandrel is restrained from moving in the axial direction and pulled out of the hollow shell. A shape guide group is mounted on the guide body, and from this U shape guide group, a U shape guide that forms a groove width corresponding to the mandrel diameter is selected, and the state is switched to the selected shape U guide.
The guide body is tilted and supported in the mandrel traveling direction so as not to hinder the movement of the mandrel during normal rolling, and at the same time, the guide body is supported during abnormal rolling and supported by a guide bed that restrains the movement in the mandrel traveling direction. A method for emergency pulling out of a mandrel, wherein a U-shaped guide restrains movement of a hollow shell inserted through the mandrel and pulls out the mandrel from the hollow shell. 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. 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 the end of rolling or when necessary,
A mandrel mill characterized by restraining the movement of the hollow shell inserted through the mandrel and pulling out the mandrel from the hollow shell during abnormal rolling by the mandrel emergency pulling method according to claim 2.

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