JPH0280108A - Method and device for manufacturing seamless tube - Google Patents

Abstract

PURPOSE:To prevent deflection of a seamless steel tube by pinching a mandrel bar with plural pinch rollers and pinching a hollow shell with these rollers by separating and approaching these rollers each other when the hollow shell moves between the rollers. CONSTITUTION:Advancing force and rotating force are given to a billet B1 by work rolls M and the billet B1 is pierced by a plug P at the top of a mandrel bar A and is transferred toward the down stream side along the periphery of the bar A. The billet B1, that is, a hollow shell B2 is detected by a sensor in immediately front of a holding device H and respective pinch rollers 4, 12, 22 are separated from the shell B2 not to interrupt straight advancing motion of the shell B2. Respective pinch rollers are separated from the bar A by actuating a 2nd hydraulic cylinder 15. After passage of the shell B2 between respective pinch rollers, the shell B2 is pinched with respective supporting rollers by actuating 1st and 2nd hydraulic cylinders 14, 15. After completion of a piercing stage for the billet B1, respective rollers are separated from the shell B2. Hence, thickness deviation of a seamless steel tube is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a Mannesmann type seamless pipe manufacturing method and apparatus, and more particularly to improvements in piercers and elongators.

[Conventional technology]

Generally, in Mannesmann type hot seamless steel pipe manufacturing equipment, when drilling with a piercer, a work roll applies thrust and rotational force to the billet, generating high stress in the center of the billet, and placing the hole on the downstream side in the direction of billet movement. The billet is then perforated with a plug supported by a mandrel bar. At this time, the plug and the mandrel bar supporting the plug also rotate at high speed due to the frictional force between the billet and the plug. In order to guide the rotation of the mandrel bar and restrict its whirling, a device called a bar stepper, which includes a plurality of rollers arranged around the mandrel bar, is used to stabilize the rotation of the mandrel bar.

Then, when the hollow shell formed by the hole formed by the plug at the tip of the mandrel bar moves and comes to the position of this bar step ear, this bar step ear is opened in the radial direction larger than the outer diameter of the hollow shell, which obstructs the feeding of the hollow shell. be evacuated to prevent this from happening.

[Problem to be solved by the invention]

In this state, when the hollow shell is rotated at high speed,
There is a problem in that the whirling of the center locus of the hollow shell becomes large, causing uneven thickness in the seamless steel pipe, or resonance, which causes vibrations and noise.

In an attempt to solve such problems, conventionally, guide members having guide holes slightly larger than the shell diameter are provided at the front and rear of the bar step ear, and the guide holes are used to restrict the rotational swing of the hollow shell. Further, the degree of opening of the rollers is made as small as possible to reduce the gap between the roller of the bar stepper and the outer periphery of the hollow shell, and the swinging of the hollow shell is restricted by bringing the roller closer to the outer periphery of the hollow shell.

However, depending on the above method, it is not possible to completely eliminate the gap between the inner periphery of the guide hole of the guide member and the outer periphery of the hollow shell, so it is not possible to sufficiently reduce the whirling of the center trajectory of the hollow shell. , there was a problem that it caused uneven thickness of seamless steel pipes. A similar problem also exists in an elongator for further enlarging the diameter of a hollow shell formed by piercing a billet with a piercer.

The present invention has been made in view of the above problems, and includes:
By holding the hollow shell with a plurality of holding rollers that hold the mandrel bar, the mandrel bar and the hollow shell can be held in a stable state, the swinging of the center locus of the hollow shell can be reduced, and uneven thickness of the seamless pipe can be reduced. The purpose of the present invention is to provide a method for manufacturing a seamless pipe and an apparatus therefor.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a method for manufacturing seamless pipes in which a work roll applies thrust and rotational force to a circular cross-sectional material, and a plug attached to the tip of a mandrel bar perforates the circular cross-sectional material. Alternatively, in a method for manufacturing a seamless pipe in which a hollow shell is obtained by expanding the diameter, a plurality of clamping rollers that clamp the mandrel bar are moved away from each other and approached, so that the perforated or rolled hollow shell is sent to the position of the clamping rollers. The feature is that the hollow shell is held in place when it is carried.

In addition, the device is a seamless pipe in which a work roll applies thrust and rotational force to a circular cross-section material, and a plug attached to the tip of a mandrel bar perforates or expands the diameter of this circular cross-section material to obtain a hollow shell. A manufacturing device comprising: a plurality of clamping rollers that surround a mandrel bar and are arranged so as to be able to move away from each other; and a fluid pressure cylinder that interlocks these clamping rollers via a link mechanism to move the clamping rollers toward and away from each other. It is characterized by the presence of

[Effect]

With the above configuration, the mandrel bar is first held between a plurality of holding rollers, and when the hollow shell moves, the fluid pressure cylinder is actuated to separate and approach these holding rollers via a link mechanism, and the hollow shell is held between them. It is held between rollers to restrict the whirling of the center locus of the hollow shell.

〔Example〕

Embodiments of the present invention shown in the drawings will be described below.

FIG. 1 shows a manufacturing apparatus according to the present invention, in which opposing base frames 1.1 are arranged below both sides of the pass line W, and a state in which the base frames 1.1 straddles between the base frames 1 and 1 on the upper side. A rectangular first frame 2 is disposed, and a lever shaft 3 whose axis extends in the direction of the pass line is pivotally supported below the pass line W in the first frame 2. This lever shaft 3 has a first clamping roller 4 at the end on the side of the pass line W (right side in the figure), and a lever in the shape of an inverted character, which has a connecting rod 5 pivotally attached to the other end. 6
A lever 7 in the shape of a cross that extends long to the side of the pass line W is rotatably attached to the central part of the lever 7.

Further, at the upper end of the substantially triangular second frame 8 disposed on the base frame 1 at the - side position, there is another frame parallel to the lever shaft 3 on one side of the pass line W and on the diagonally upper side. A lever shaft 9 is pivotally mounted, and a lever 10 having an inverted shape, with one side extending diagonally upward to the side of the pass line W and the other side extending above and above the pass line W, is integrally attached at the center. At the same time, a pass line W is attached to this lever shaft 9.
- One end of the lever 11 extending laterally and diagonally upward is attached so as to be rotatable together. A second holding roller 12 is pivotally attached to the end of the portion of the lever 10 that extends above the pass line W from the lever shaft 9, while a hollow cylindrical trunnion 13 is pivotally attached to the upper end diagonally above the - side. It is worn.

Also, the height of the edge of the frame 8 on the lever 11
The rond tip of the first fluid pressure cylinder 14 is pivotally mounted in the middle. Also - base frame l in lateral position
A second fluid pressure cylinder 15 is pivotally attached to one side of the cylinder 15, and the tip of the cylinder 15 is pivotally supported to the end of the lever 7 on the side of the pass line W. Then, the upper end of a connecting rod 16 whose lower end is pivotally attached to the upper end of the upward portion of the lever 7 is slidably inserted into the hollow part of the trunnion 13, and a locking nut 17 is screwed onto the upper end of the connecting rod 16. This prevents the connecting rod 16 from coming off the trunnion 13. Then, the center point a of the lever shaft 3, the upper end of the lever 7 and the connecting rod 16
The pivot point C between the connecting rod 16 and the lever 10 and the center point d of the lever shaft 9 form a parallelogram. The position, dimensions, etc. of the lever 10, the lever 7, and the connecting rod 16 constitute a link mechanism.

Further, a connecting rod 5 pivotally attached to the lower end of the other side of the lever 6 extends diagonally upward on the other side (left side in the figure), and is disposed on the base frame 1 on the other side. A lever shaft 1 parallel to the lever shaft 3.9 is located at the upper end of the triangular third frame 8 and on the other side of the pass line W.
9 is pivoted. Then, levers 20 and 21 are attached to this lever shaft 19, one side facing the pass line W and the other side facing downward.
The connecting rod 5 is integrally rotatably attached in an L shape so that the other side faces downward on the pass line W side, and the upper end of the connecting rod 5 is pivoted to the lower end of one lever 20 that faces downward on the other side of the pass line W. A third clamping roller 22 is pivotally attached to the lower end of the other lever 21 facing downward on the pass line W side. The center point a of the lever shaft 3, the pivot point e of the connecting rod 5 and the lever 6, and the center point e of the connecting rod 5 and the lever 2.
The position, dimensions, etc. of each member are determined so that the quadrilateral formed by the pivot center point f with respect to the lever shaft 19 and the center point g of the lever shaft 19 becomes a parallelogram, and the lever 6 and the connecting rod 5 are The lever 20 constitutes a link mechanism.

In addition, the lever shafts 9°3.
The lengths from the center points d, a, and g of the rollers 19 to the pivot point of the clamping rollers are formed to have the same dimensions.

In addition, a bracket 2 is attached to the lower end of the downward part of the lever 7.
3 is attached, and a screw jack 24 facing this bracket 23 is attached to the base frame 1, so that the rotation range of the lever 7 is regulated by the contact of this bracket 23 with the screw jack 24. There is. Incidentally, as shown in FIG. 3, a plurality of holding devices H are provided in the feeding cylinder of the hollow shell B2.

FIG. 2 is an explanatory diagram showing the approaching and separating states of each clamping roller 4, 12, and 22 with respect to the pass line W, mandrel bar A, and hollow shell B2.
Fig. 2 shows a state in which each of the pinching rollers 4, 12, 22 is separated from the center of the mandrel bar A, and Fig.
Fig. 2(C) shows a state in which each holding roller 4°12.22 is separated from the hollow shell B2, and Fig. 2(d) shows a state in which each holding roller 4°12.22 is separated from the hollow shell B2. 4.12.22 approaches Hollow Shell B2
It shows the state where it is being held.

In addition, Fig. 4 shows the process of perforating billet B1 with a plug P attached to the tip of mandrel bar A.
C) shows the state during drilling, and FIG. 4 (dl shows the state when drilling is completed).

With the above configuration, the mandrel bar A (see FIG. 3) is moved from the position where each clamping roller 4, 12, 22 is apart from the pass line W as shown in FIG. 2(a) to each clamping roller. 4.12.22, the first hydraulic cylinder 14 and the second hydraulic cylinder 15 are driven to extend each rod, the lever 10.11 is rotated counterclockwise, 2 [0 While moving the roller 12 toward the center of the pass line W, the trunnion 13
comes into contact with the retaining nut 17, and the connecting rod 16
is pulled upward, the lever 7.6 is rotated counterclockwise about the lever shaft 3, and the first holding roller 4 is moved toward the center of the pass line W. Also, by rotating the lever 6 in the counterclockwise direction, the connecting rod 5 is moved to the first position.
The lever 20.21 is pulled diagonally downward to the right in the figure.
rotates counterclockwise, and the third holding roller 22 is moved toward the center of the pass line W.

Then, by moving each of the clamping rollers 4.12.22 toward the center of the pass line W, each of the clamping rollers 4.12.
The mandrel bar A is clamped by 22.

Next, as shown in Fig. 3, the production of seamless pipes is started, and the work roll M applies thrust and rotational force to the billet B1, and the plug P attached to the tip of the mandrel bar A causes the billet to B1 is perforated and sent downstream along the outer periphery of mandrel bar A. When the billet 81, that is, the hollow shell B2, which has been perforated by the plug P attached to the tip of the mandrel bar A, is positioned immediately in front of the holding device H, a sensor (not shown) provided at an appropriate position detects the hollow shell B2. As shown in FIG.
Separate them from each other in the radial direction at equal intervals.

To separate each clamping roller 4.12.22 from the shell B2, the second hydraulic cylinder 15 can then be actuated to retract the rod. At this time, the fluid pressure of the first fluid pressure cylinder 14 is weakened to such an extent that the operation of the second fluid pressure cylinder 15 is not hindered. With the above-mentioned operation of the second fluid pressure cylinder 15, the lever 7, lever IO, and lever 6 are rotated clockwise, and the second clamping roller 12 and the first clamping roller 4 are rotated clockwise.
and leaves the mandrel bar A. At the same time, the connecting rod 5 moves diagonally upward to the left in FIG. 1, the levers 20.21 rotate clockwise, and the third clamping roller 22 separates from the mandrel bar A. As described above, since the linear distances from the pivot points d, a, g of the lever 10 and the lever 6.21 to the tips of the respective clamping rollers 4, 12, 22 are the same, each of the clamping rollers 4, 12, .
22 and the outer circumferential surface of the mandrel bar A are equally spaced. Further, when the second fluid pressure cylinder 15 is operated, the lever 11 also rotates clockwise, so that the rod of the first fluid pressure cylinder 14 enters into the cylinder 14. At the same time, when the lever 7 rotates clockwise, the bracket 23 attached to the lower part of the lever 7 comes into contact with the tip of the screw jack 24, and the rotation of the lever 7 is restricted.
The distance between each nipping roller 4.12.22 from the outer peripheral surface of the mandrel bar A is limited. Then, each pinching roller 4, 1
2゜22 is hollow shell B2 as shown in Fig. 2(C)
It is held with a slight gap from the outer circumferential surface of the

After the hollow shell B2 is sent in the rolling direction and passes between the respective nipping rollers 4, 12, 22, the first fluid pressure cylinder 14 is activated, and the second fluid pressure cylinder 15 is additionally activated to Extend the rod and rotate the lever 10.11 clockwise to release the second clamping roller 12.
is moved toward the center of the pass line W. At the same time,
In the same manner as when mandrel bar A is held between each holding roller 4, 12, and 22, the remaining first holding roller 5 and third holding roller 22 are connected to each other via connecting rods 16, 5, etc.
are moved toward the center of the pass line W, and the hollow shell B2 is held between the holding rollers 4 and 12 degrees 22 as shown in FIG. 2(d).

At this time, hollow shell B2 has less rigidity than mandrel bar A and is easily deformed.
Considering the material, outer diameter and wall thickness of 2, hollow shell B2
The first fluid pressure cylinder 1 is moved so that each clamping roller 4.12.22 contacts the hollow shell B2 with an appropriate force that does not deform the cylinder.
The adjustment is made by changing the fluid pressure between the fluid pressure cylinder 4 and the second fluid pressure cylinder 15 used auxiliary.

In addition to changing the fluid pressure, the force can be adjusted by applying pressure to the head side and the rond side and using it as a differential cylinder, or by applying pressure to the rond side of the cylinder 15 to adjust the force of the cylinder 14 to an appropriate level. It is necessary to adjust the force over a wide range using methods such as counteracting.

When the punching process of the billet B1 is completed, as shown in FIGS. 2(a) and 4(d), each clamping roller 4, 12, 22 is retracted by the operation of the second fluid pressure cylinder 15. are separated from each other to form hollow shell B.
After releasing from 2, mandrel bar A and hollow shell B
2 is discharged to the outside of the holding device H9H... by a predetermined device.

In this way, the mandrel bar A is held between the plurality of holding rollers 4.12.22 that can move toward and away from each other, while the holding rollers 4.12.22 are moved away from each other and then brought closer to hold the hollow shell B2. Since the mandrel bar A and the hollow shell B2 are perforated and delivered, the mandrel bar A and the hollow shell B2 are stably restrained, and the whirling of the center locus of the hollow shell B2 can be reduced, thereby reducing uneven thickness of the seamless pipe. Can be done.

Next, by the method and apparatus of the present invention, the hollow shell B
The test results obtained by manufacturing No. 2 will be described below.

The outer diameter of hollow shell B2 is 244.5 *■, and the wall thickness is 1
2. In the case of 41 cranes weighing 950 kg, the thickness deviation rate was 13.1% on average when carried out using the conventional equipment, as shown in the graph in Figure 6, but the graph in Figure 5 As shown in , the average reduction was 11.7% when using the apparatus of the present invention.

Although this embodiment has been described in which the present invention is applied to a piercer, the present invention is not limited to this, but can also be applied to an elongator that expands the diameter of a hollow shell.

〔Effect of the invention〕

Since the present invention has the above-mentioned configuration and functions, it has the advantage that the hollow shell can be stably clamped and uneven thickness of the seamless pipe can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an embodiment of the seamless pipe manufacturing apparatus according to the present invention, FIG. An explanatory diagram of a state in which the mandrel bar is clamped by each clamping roller. Figure 2 (C) is an explanatory diagram of a state in which the clamping rollers are separated from each other by a predetermined distance and a hollow shell is passed between them.
dl is an explanatory diagram of a state in which a hollow shell is clamped by each clamping roller, and Fig. 3 is an explanatory diagram of a state in which a hollow shell is clamped by each clamping roller.
and a schematic plan view of the state in which the hollow shell is clamped, and FIG. ) is a schematic plan view of the mandrel bar and the hollow shell being held between the respective clamping rollers after the billet drilling process has progressed, and Figure 4fd) is a schematic plan view of the billet after the billet drilling process has been completed and the clamping rollers are held together. FIG. 5 is a schematic plan view of the separated state; FIG. 5 is a graph showing the uneven thickness that occurs in the hollow shell when a billet is perforated while the hollow shell is held in the holding device according to the present invention; FIG. It is a graph showing the thickness unevenness rate that occurs in a hollow shell when a billet is perforated with a device. A... Mandrel bar B1... Billet B2...
Hollow shell 4.12.22... clamping roller 14,
15...Fluid pressure cylinder patent Applicant Sumitomo Metal Industries Co., Ltd. Agent Patent attorney Noboru Kawano

Claims (1)

[Scope of Claims] 1. A seamless pipe in which a hollow shell is obtained by applying thrust and rotational force to a circular cross-sectional material from a work roll, and drilling or expanding the diameter of this circular cross-sectional material with a plug attached to the tip of a mandrel bar. In the manufacturing method, a plurality of clamping rollers that clamp the mandrel bar are separated from and approached each other, so that when the hollow shell that has been perforated or rolled is sent to the position of the clamping rollers, the hollow shell is clamped. Features: Seamless pipe manufacturing method. 2. In a seamless pipe manufacturing device in which a work roll applies thrust and rotational force to a circular cross-section material, and a plug attached to the tip of a mandrel bar perforates or expands the diameter of this circular cross-section material to obtain a hollow shell. , comprising a plurality of clamping rollers that surround the mandrel bar and are arranged so as to be able to move away from each other, and a fluid pressure cylinder that interlocks these clamping rollers via a link mechanism to move them toward and away from each other. Seamless pipe manufacturing equipment.