JPS5992107A - Reduced thickness rolling method by reduced thickness rolling device for pipe end in installation for producing seamless steel pipe - Google Patents

Abstract

PURPOSE:To obtain a seamless steel pipe which is smoothly reduced in thickness at the end of a hollow blank pipe by adjusting relatively the revolving speed and rotating speed of rolling rolls to prevent the roling rolls from exterting rotating torque on the end of the hollow pipe. CONSTITUTION:The rear end of a hollow blank pipe 6 is fed by feed rolls 39 into the working center of a reduced thickness rolling device 12 for rear end. A mandrel 13 and rolling rolls 14 are advanced respectively in the axial direction by a set distance and thereafter the rolls 14 are set in rolling down positions. A driving device 21 for revolution and a driving device 28 for rotation are operated to bring the rolls 14 into contact with the outside peripheral part at the end of the pipe 6 in the state of revolution and rotation. The revolving speed and rotating speed of the rolls 14 are relatively adjusted to prevent the rolls 14 from exerting rotating torque on the end of the pipe 6. The pipe 6 is made movable axially in a non-rotating state. The rolls 14 roll the end of the blank pipe to reduce its thickness at a preset ratio of thickness reduction, that is, the ratio of the thickness reduction at which the increased thickness to be added to the end of the pipe 6 by reducing with a succeeding stretch reducer 8 can be offset.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thinning rolling method using a tube end thinning rolling device in a seamless pipe manufacturing facility.

The manufacturing process for seamless steel pipes consists of a drilling process in which a hole is made in a round steel piece, an elongation rolling process in which the perforated hollow pipe is stretched to reduce its thickness, and the elongated and rolled hollow wood pipe is squeezed to a predetermined outer diameter rc. It consists of three steps: finish rolling.

That is, in a typical manufacturing process for seamless steel pipes using a mandrel mill, for example, a round steel billet 1 is heated to a predetermined temperature in a rotary hearth heating furnace 2 at 5K, as shown in FIG. Thereafter, it is pierced and rolled by a viaser mill 3 serving as a pierce rolling mill, and then stretched and rolled by a mandrel mill 5 serving as a stretching mill with a mandrel bar 4 inserted therein. 2 by mandrel mill 5
The hollow tube 6 that has been stretched to double or quadruple its length is reheated in a reheating furnace 7 if necessary, and then rolled into a finished tube 9 by a stretch reducer 8 serving as a finishing mill. .

By the way, in the stretch reducer 8, the hollow blank tube 6 into which no mandrel bar is inserted is reduced and rolled by a large number of rows of roll stands each having an oval hole shape.
The finished tube 9 with a predetermined outer diameter and wall thickness is ready for molding. Here, the diameter of each roll hole in the continuous row of roll stands of the stretch reducer 8 is set so that the later the stage, the smaller the diameter, and the roll hole of the final roll stand is set to a predetermined outer diameter of the finished tube 9. The dimensions are made to be corresponding, thereby making the outer surface of the finished g9 suitable for finishing molding. Here, the wall thickness of the hollow tube 6 formed in the trench reducer 8 becomes thicker as its outer diameter is reduced to a smaller diameter by the roll holes of each roll stand (and becomes thicker as it passes through the oval holes). There is a problem in that the deformation of the tube at each circumferential direction becomes non-uniform, resulting in non-uniform wall thickness, making it impossible to obtain a finished pipe 9 of good quality.

In order to eliminate the above-mentioned disadvantages (in the conventional seamless steel pipe manufacturing process, when rolling the hollow shell tube 6 by trench reduction, tension is applied in the axial direction of the hollow shell tube 6 between each roll stand. While applying force, hollow tube 6
At the same time, the tensile force is controlled by the roll rotation g = speed of each roll stand.
1) It is possible to suppress the increase in the thickness or reduce the thickness, and to obtain a finished pipe 9 with a predetermined wall thickness.

However, even with the above-mentioned conventional seamless steel pipe manufacturing method, the tensile force between the roll stands is generated at both ends of the hollow pipe 6 between passing one roll and biting into the next roll. cannot be given enough. In other words, it becomes impossible to remove the nonuniform wall thickness due to the J5η thickness at both ends of the hollow tube 6, and it becomes necessary to cut off the thickened portions that occur at both ends 1913 of the finished tube 90.

The cutoff amount of the thickening ff1f at both ends of the finished tube 90 varies depending on the outside diameter reduction rate in the stretch reducer 8 or the degree of control of the roll rotation speed in each 1"-le stand, etc. The ratio of the length cut off at both ends to the total length reaches about 5 inches on average.

Therefore, in order to ensure that the wall thickness of the finished pipe obtained by reduction rolling is uniform in the entire longitudinal direction, the present applicant has made the following efforts based on the specification and drawings attached to the application of Japanese Patent Application No. 56-74604. [perforated, 9] [-stretched t
1 (a core metal inserted into the inner circumference of the end of the hollow tube)
It has a rolling roll that revolves and rotates in contact with the outer periphery of the end of the hollow shell into which the core metal is inserted, and that rolls down the end of the hollow shell, and the roll roll rolls the end of the hollow shell into which the core metal is inserted, and rolls down the end of the hollow shell, and Is it covered by subsequent reduction rolling? We have already proposed a thinning rolling method using a tube end thinning rolling device in a seamless steel pipe production facility that enables the wall thickness of the thickened portion added to the end of a wood pipe to be reduced in advance.

However, what is the self-reducing rolling method using the pipe end thinning rolling device in the seamless steel pipe manufacturing equipment already proposed above? In the case of E, the rolling roll applies rotational torque to the end of the hollow shell due to the relative relationship between the revolution speed and the autorotation speed of the rolling roll.

Finished pipe product by twisting the end of the hollow pipe]
d is considered defective. In addition, if the hollow shell tube is not fixedly held by pinch rolls or the like during thickness reduction 14[times] by rolling rolls, the long hollow shell tube is subjected to pressure at the end of -1- rotation. Swings around due to torque, improving rolling workability by 1
It will cause some damage.

The present invention enables smooth thinning of the end portion of the hollow tube without applying rotational torque to the end portion, and ensures the wall thickness of the hollow tube obtained by reduction rolling in the entire 1φ direction. It is an object of the present invention to provide a thinning rolling method using a tube end thinning rolling device in a seamless copper tube manufacturing facility that makes PC uniform.

In order to achieve the above object, the present invention provides a core metal inserted into the inner circumference of the end of a hollow tube that has been perforated and stretched and rolled;
a rolling roll that revolves and rotates in contact with the outer periphery of the end of the hollow shell into which the core metal is charged, and that rolls down the end of the hollow shell, and the rolling roll is provided after the elongation and rolling. A wall thinning rolling method using a pipe end thinning rolling device in a seamless copper pipe manufacturing facility that enables the wall thickness of the thickened portion added to the end of the hollow mother pipe by rolling to be reduced in advance, the method comprising: In order to avoid applying rotational torque (l) to the 91-way portion of the hollow shell, the revolution rotation law of the Shotom roll 1.
Let l'j- and rotational speed be aligned with each other/
It's a small thing.

1'tF, the present invention will be explained in detail with reference to the drawings.

FIG. 2 is a side view, partially cut away, of an example of a tube end thinning rolling apparatus used for carrying out the present invention, and FIG. 3 is a front view of FIG. 2.

The tube end thinning rolling device 12 shown in FIGS. 2 and 3 is located between the mandrel mill 5 and the reheating furnace 7 in the general seamless steel pipe manufacturing process shown in FIG. The end portion of the hollow tube 6 that has been elongated and rolled by the mandrel mill 5 can be rolled to reduce its thickness. That is, the tube end thinning rolling device 12 has a core metal 13 inserted into the inner circumference of the beveled portion of the hollow tube 6.

The core metal 13 is brought into contact with the outer periphery of the inserted hollow pipe 6 in a state of revolution and rotation, and the center of the six hollow wood pipes j
Three rolling rolls 14 with a rolling opening in the J-direction are installed.
The ends of the hollow tube 6 are rolled so that the wall becomes thinner toward the outer end in the axial direction. Each pressure sill roll 14 is supported 1q by the chock part 158 of each reduction device 15.
h 14 A, and the inner part of the core bar 13 [,
It is possible to move forward and backward in one direction. The lowering device 15 includes a -9114 portion 13Arc of a revolving housing 18 which is rotatably supported coaxially with respect to the core metal 13 via a liliI support 17 on a pedestal 16, and three parts in the circumferential direction around the core metal 13. The arrangement IMN IC is arranged so that each rolling roll 14 can come into contact with the outer circumference of the end of the hollow tube 6 into which the cored metal 13 is inserted, in a state of revolution and rotation. Furthermore, during the rotation of the rolling roll 140, the shaft legs are set at h times that are different from the center axes of the core metal 13 and the hollow blank tube 6, and the rolling roll 14 revolves around the outer periphery of the hollow blank tube 6. When they rotate and come into contact with each other, a relative helical motion can be generated between the hollow shell 6 and the rolling rolls 14. A gear 19 is attached to the outer periphery of the end of the revolving housing 18 opposite to the lowering device 15, and the revolving housing 18 has a driving gear 20 that meshes with the teeth IJL19.
It is designed to be rotationally driven by a revolution drive device 21 via.

14 supports + 1qll 14 A O,) on the said rolling n-
&i°16 part niha, the shaft of a gear 22 supported on the inner peripheral side of the revolution housing 18 is connected via a universal joint 23. The gears 22 are arranged at three equal intervals on the inner periphery of the revolution housing 18 in correspondence with the rolling rolls 14, and each gear 22 has a ring shape arranged coaxially with the revolution housing 18 around the core metal 13. It is said to be a town bear that meshes with gear 24. The gear 24 is integrally provided on the outer periphery of a cylindrical sleeve 25, and the sleeve 25 has the same diameter as the core metal 13.
The metal core 13 is supported via a bearing 26 on the outer side thereof so as to be movable relative to the core metal 13 in the axial direction and rotational direction. One end of the sleeve 25 is attached to the gear 1 of the revolving housing 18.
It protrudes in the evening direction from the end on the side 9, and a ring-shaped tooth east 27 is attached to the outer periphery of this protrusion. A gear 29 attached to the output shaft of a rotation drive device 28 is meshed with the gear 27, whereby the sleeve 25 is driven 1"11 rotation around the core metal 13, and the gear 24, 22 and the eyelid
The rolling roll 14 is driven to rotate through the joint 23.

+:+il The downstream device 15 is capable of moving the mill roll 14 forward and backward in the rolling direction by rotating a pinion 310 screwed into the rolling screw 30 thereof. This binion 31 is
It meshes with a rack 32 inserted into one end 18A of the revolution housing 18 from the axial direction, and is rotated by movement of the rack 32 in the axial direction. Three racks 32 are arranged corresponding to each rolling roll 14, and one axial end of each rack is connected to a side surface of a ring 33. The outer end t' of this ring 33? lj Both sides are the previous month -
The ring 33 is inserted between a pair of fJ-ra 36 rotatably attached to the ring 35 of the device 34, thereby driving the ring 33 in the axial direction even though it does not rotate together with the revolving housing 18. It is now possible to do so.

In the figure, 37 is a wheel that allows the frame 16 to be moved, 38 is a pinch roll that pinches the hollow material tube 6 to provide a 'filing function, and 39 is a wheel that allows the hollow material tube 6 to be moved in the axial direction. J
The feeding roller 40 is a liquid IE wave device 'L that moves the core metal 13 back and forth in its axial direction. .

Next, the above-mentioned front end thinning 1. An example of the inventive rolling method using the E-moth device 12 will be explained in detail.

First, as explained in FIG. 1 of Mil's book, the rear end of the hollow shell 6 that has been pierced by the piercer mill 3 and stretched and rolled by the mandrel mill 5 is moved by the feed roller 39 to reduce the tube end for the rear end. The meat is transported to the processing center of the meat rolling device 12. Here, the pedestal 160 wheels 37 are kept stationary, the core metal 13 and the rolling rolls 14 are each waited at a retracted position in the axial direction with respect to the hollow tube 6, and the radial position of each rolling roll 14 is (roll down position) is on standby at its retracted position. When it is confirmed by, for example, a detection signal from an infrared detector that the rear end of the hollow tube 6 has been inserted into the processing position of the tube end thinning rolling device 12, the core metal 13
And the rolling rolls 14 are each advanced in the axial direction by a set distance, and then the rolling rolls 14 are set to the rolling position. Here, when the core bar 13 is advanced and inserted into the hollow wood tube 6, the hollow tube 6 is fixedly held by the pinch rolls 38.

At the same time as the setting of the rolling position of the rolling roll 14 is completed, the pinch roll 38 releases the hollow shell 6, the revolution drive device 21 and the rotation drive device 28 are activated, and the rolling roll 14 is brought into contact with the outer periphery of the end of the hollow shell 6 in a state in which it revolves and rotates on its axis. here,
Since the rotation axis of the rolling roll 140 is disposed in a direction different from the axis 7b of the hollow shell 6 and the core metal 13, the rolling roll 14 and the hollow shell 6 move in a spiral manner relative to each other. On the other hand, the pedestal 16 is held stationary. Two and power・
Based on the above-mentioned spiral movement, the hollow shell 6 moves in its axial direction, and the rolling position by the rolling rolls 14Vr- is gradually displaced toward its outer end.

Therefore, when the revolution speed and the autorotation speed of the rolling rolls 14 are arbitrarily set, the rolling rolls 14 impart rotational torque to the hollow shell 6, and the hollow shell 6 has an autoaxial opening. It moves in the axial direction in a state where it can be rotated around, and a twisting deformation occurs at the end of the middle nitrogen g6. Therefore, in this embodiment, the rolling roll 14 is
The revolution speed and the rotation speed of the rolling rolls 14 are mutually adjusted so as not to impart rotational torsion to the filS, and the hollow shell 6 can be moved in its axial direction without being rotated.

In this way, the hollow shell 6 is prevented from rotating (as it moves in the axial direction, the rolling rolls 14 are rotated at a preset thickness reduction rate, i.e., the subsequent trench resuser 8
Each part in the axial direction at the end of the hollow shell 6 is thinned at a thinning ratio that can offset the wall thickness increase added to the end of the hollow shell 6 and the middle 2 by the reduction rolling. . The inner rolling action by the rolling roll 14 is achieved by driving the ring 33 via the roller 36 by the hydraulic device 34, and thereby rotating the pinion 31 via the rack 32, thereby moving the rolling roll 14 into the rolling 1 position. Correct. Note that during thinning rolling by this rolling roll 14, the core metal 13
are moved protrudingly by the hydraulic device 40 in response to the axial movement of the hollow shell 6 so as not to move relative to the hollow shell 6, thereby causing the rolling rolls 14 to move around the hollow shell 6. 6 is being rolled for thickness reduction, the core metal 13 is maintained in the charged state with respect to the nitrogen pipe 6.

In this way, when the thinning rolling of the rear end portion of the hollow shell 6 is completed, the rolling position of the rolling roll 14 is opened, and the core metal 13 is opened.
is retracted by the hydraulic device 40 and pulled out from the hollow shell 6. The hollow blank tube 6 whose rear end has been subjected to thinning rolling is then carried into the processing center of the tube end thinning rolling device for the front end C1, and the front end is reduced in the same way as the rear end. Meat rolling is done.

FIG. 4 shows the effect on the hollow shell 6 to be thinned by adjusting the revolution rotation speed N and the autorotation rotation speed N2 of the tube end thinning rolling device 12 as in the second embodiment. It is a diagram showing a state in which the rotational torque is eliminated and the torsional deformation applied to the end of the hollow steel pipe 6 is eliminated. Note that the revolution rotation direction and the autorotation rotation direction of the 1F rolling roll 14 are as follows. , for example, are in the same direction when viewed from the front as shown in FIG.

That is, this figure 4 shows a hollow blank tube 6 with an outer diameter of 89.0 -, a wall thickness of 645t+tm, and a length of 2500mm.
At the end of 1. When performing 2 m-thickness reduction, the rolling temperature is 950°C, the roll inclination angle is 6 degrees, the roll shape is straight cylindrical, the rotational speed N2 is constant 35° 7RPM, and the revolution speed is 70 to 18 This figure shows the results of measuring the surface twist angle δ of the hollow wood pipe 60 die after thinning rolling by changing the angle between Il It l)M as appropriate. According to FIG. 4, by adjusting the speed ratio N2/N1 between the rotation speed and the revolution speed, the torsion angle 1δl of the outer surface of the hollow tube 6 changes greatly, and in particular, the speed ratio N2/N1 changes greatly. By selecting Nl near 035,
It is recognized that it is possible to set the torsion angle 1δ1 to the minimum and sail the hollow tube 6 with reduced thickness while sending it out in a substantially straight direction without rotating it.

In the embodiment described in "-", a case has been described in which the hollow shell 6 is released from the pinch rolls 38 during internal reduction rolling by the rolling rolls 14 in the pipe end thinning apparatus 12.

However, in the tube end thinning rolling device 12, when thinning is carried out by the rolling rolls 141ζ, the pinch rolls 38
If the present invention is applied when fixing the hollow tube 6 by In this case, along with the axial movement of the rolling roll 14, the pedestal 16 can be moved in the axial direction.
is moved via wheels 37.

Naive, the above embodiment is based on the present invention in a tube end thinning rolling device 12 using rolling rolls 14 which are arranged in different directions with respect to the hollow tube 6 and move relative to each other in the axial direction of the hollow tube 6. We have explained the case where it is applied. however,
The present invention provides a tube end thinning rolling device or a tube end thinning rolling device in which the rolling rolls are not arranged in the opposite direction with respect to the hollow mother tube and is provided with other means for moving the rolling rolls and the hollow wood tube relative to each other in the axial direction. It can also be used in tube end thinning rolling equipment, etc., which uses rolling rolls having a roll width equal to or greater than the length of the end of the hollow tube to be thickened, and which does not require relative movement of the rolling roll and the hollow tube in the axial direction. Applicable.

In addition, the present invention is not only used in the manufacturing process of seamless steel pipes based on the mandrel mill method (but can also be applied to the manufacturing process of seamless steel pipes using other rolling methods such as the Zorlag mill method). .

As described above, the present invention provides a core metal inserted into the inner periphery of the end of a hollow tube that has been perforated and drawn and rolled, and a core metal inserted into the outer periphery of the end of the hollow tube into which the core metal is inserted. and a rolling wheel that rotates and rotates to abut and roll down the &f "a part" of the hollow mother tube, and the end portion iK of the hollow mother tube is added by the reduction rolling that follows the elongation rolling. Seamless/A″4 pipe j″h that allows the wall thickness of the JVI wall to be reduced in advance
An inner rolling method using a tube end thickness thinning rolling device in equipment, wherein the rotational speed and the autorotation rotational speed of the rolling rolls are adjusted so that the rolling rolls do not apply rotational torque to the ends of the MiJ hollow wood pipes. Since the ends are mutually adjusted, the end portion can be turned into a circle without applying rotational torque to the WMa ilj of the hollow tube. The most important thing to do is to ensure that the wall thickness of the finished pipe obtained by reduction rolling is uniform in the entire longitudinal direction.

[Brief explanation of drawings]

Figure 1 shows the layout 14 of a typical seamless steel pipe manufacturing process.
Fig. 2 is a partially cutaway side view showing an example of pipe end wall thinning 1] used in the practice of the present invention, and Fig.
The front view of the figure and FIG. 4 are diagrams showing the influence of the speed ratio of the revolution rotation speed and the autorotation rotation speed in the end reduction internal rolling apparatus on the torsional deformation of the blank pipe. 3°°° Heather Mill, 5°゛° Mandrel Mill. 6...Hollow tube, 8...Stretch reducer. 12... Tube end thinning rolling device, 13... Core bar, 14...
...FF rolling roll, 15... Reduction device, 21... Revolution drive device, 28... Autorotation drive device. Agent Patent Attorney Osamu Shiokawa

Claims (1)

[Claims] (1) A core metal is inserted into the inner periphery of the end of a hollow tube that has been drilled and stretched, and the core metal is inserted into the outer periphery of the end of the hollow tube into which the core metal is inserted. and rolling rolls that are in contact with each other and roll down the ends of the hollow shell, and the inside of the hollow tube is rolled by a reduction roll that follows the elongation and rolling. A wall thinning rolling method using a pipe end thinning rolling device in a seamless steel pipe manufacturing facility that enables the thickness increase added to the end of a blank pipe to be reduced in advance, wherein the rolling roll is used to reduce the wall thickness of the hollow blank pipe. A thinning rolling method using a tube end thinning rolling device in a seamless steel pipe manufacturing facility in which the revolution rotation speed and the autorotation rotation speed of the rolling rolls are mutually adjusted so as not to apply rotational torque to the ends of the rolls.