U.S. patent application number 13/343319 was filed with the patent office on 2012-06-21 for device for adjusting rolling positions of rolling rolls constituting three-roll mandrel mill and method for manufacturing seamless pipes or tubes.
This patent application is currently assigned to SUMITOMO METAL INDUSTRIES, LTD.. Invention is credited to Shigeru KIDANI, Akihito YAMANE.
Application Number | 20120151979 13/343319 |
Document ID | / |
Family ID | 43586134 |
Filed Date | 2012-06-21 |
United States Patent
Application |
20120151979 |
Kind Code |
A1 |
YAMANE; Akihito ; et
al. |
June 21, 2012 |
DEVICE FOR ADJUSTING ROLLING POSITIONS OF ROLLING ROLLS
CONSTITUTING THREE-ROLL MANDREL MILL AND METHOD FOR MANUFACTURING
SEAMLESS PIPES OR TUBES
Abstract
A device for adjusting the rolling positions of rolling rolls
and restraining poor roll-biting of the front edge part of a pipe
material rolled by a three-roll mandrel mill includes pressing-down
devices 1 (P1 to P6) for moving rolling rolls R1 to R6 in the
rolling direction and a control unit 2 for controlling the
pressing-down devices 1. Immediately after the front edge part of a
pipe material T has begun to be rolled by the rolling rolls
disposed on at least one rolling stand of the rolling rolls R1 to
R6, the control unit 2 controls the pressing-down device 1 to move
the rolling rolls in the closing direction. Preferably, the rolling
rolls disposed on at least one rolling stand of the rolling rolls
R1 to R6 in the closing direction are moved at a speed of 16 mm/sec
or higher using the pressing-down device 1.
Inventors: |
YAMANE; Akihito; (Osaka,
JP) ; KIDANI; Shigeru; (Osaka, JP) |
Assignee: |
SUMITOMO METAL INDUSTRIES,
LTD.
Osaka
JP
|
Family ID: |
43586134 |
Appl. No.: |
13/343319 |
Filed: |
January 4, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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PCT/JP2010/063060 |
Aug 3, 2010 |
|
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13343319 |
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Current U.S.
Class: |
72/12.5 |
Current CPC
Class: |
B21B 2261/10 20130101;
B21B 37/78 20130101; B21B 2273/16 20130101; B21B 37/62 20130101;
B21B 2271/02 20130101; B21B 38/00 20130101; B21B 2273/14 20130101;
B21B 17/04 20130101; B21B 2275/06 20130101; B21B 37/58
20130101 |
Class at
Publication: |
72/12.5 |
International
Class: |
B21B 37/58 20060101
B21B037/58; B21B 37/78 20060101 B21B037/78 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 11, 2009 |
JP |
2009-186374 |
Claims
1. A device for adjusting the rolling positions of rolling rolls
disposed on at least one rolling stand constituting a three-roll
mandrel mill, the device comprising: a pressing-down device for
moving the rolling rolls in the rolling direction; and a control
unit for controlling the pressing-down device, wherein immediately
after a front edge part of a pipe or tube material has begun to be
rolled by the rolling rolls, the control unit controls the
pressing-down device to move the rolling rolls in the closing
direction.
2. The device for adjusting the rolling positions of rolling rolls
constituting a three-roll mandrel mill according to claim 1,
wherein the control unit moves the rolling rolls in the closing
direction at a speed of 16 millimeters per second or higher by
using the pressing-down device.
3. A method for manufacturing seamless pipes or tubes, wherein a
three-roll mandrel mill that adopts the device for adjusting the
rolling positions of rolling rolls described in claim 1 is
used.
4. A device for adjusting the rolling positions of rolling rolls
disposed on at least one rolling stand constituting a three-roll
mandrel mill, the device comprising: a pressing-down device for
moving the rolling rolls in the rolling direction; and a control
unit for controlling the pressing-down device, wherein immediately
after a rear edge part of a pipe or tube material has begun to be
rolled by the rolling rolls, the control unit controls the
pressing-down device to move the rolling rolls in the closing
direction.
5. The device for adjusting the rolling positions of rolling rolls
constituting a three-roll mandrel mill according to claim 4,
wherein the control unit moves the rolling rolls in the closing
direction at a speed of 16 millimeters per second or higher by
using the pressing-down device.
6. A method for manufacturing seamless pipes or tubes, wherein a
three-roll mandrel mill that adopts the device for adjusting the
rolling positions of rolling rolls described in claim 4 is used.
Description
TECHNICAL FIELD
[0001] The present invention relates to a device for adjusting the
rolling positions of rolling rolls constituting a three-roll
mandrel mill used for manufacturing seamless pipes or tubes. More
particularly, the present invention relates to a rolling position
adjusting device capable of restraining poor roll-biting of the
front edge part of a pipe or tube material rolled by a three-roll
mandrel mill or capable of restraining a decrease in
circumferential length of the rear edge part of the pipe or tube
material. Hereinafter, "pipe or tube" is referred to as "pipe" when
deemed appropriate.
BACKGROUND ART
[0002] As a mandrel mill that is equipment for manufacturing
seamless pipes, a two-roll mandrel mill has conventionally been
used in which two opposed rolling rolls (grooved rolls) are
disposed on respective rolling stands, and are arranged alternately
so that the rolling direction of rolling roll of a rolling stand is
shifted by 90 degrees from that of an adjacent rolling stand. Also,
a three-roll mandrel mill has been used in which three rolling
rolls (grooved rolls) are disposed on respective rolling stands so
that the angle between the rolling directions is 120 degrees, and
are arranged alternately so that the rolling direction of rolling
roll of a rolling stand is shifted by 60 degrees from that of an
adjacent rolling stand.
[0003] It has been known that the three-roll mandrel mill is less
liable to a problem of plastic deformation such as poor piercing of
pipe material than the two-roll mandrel mill.
[0004] Therefore, in the case where the three-roll mandrel mill is
used, to decrease the equipment size (reduce the number of rolling
stands) or to increase the manufacturing capability, it is thought
that the working ratio of pipe material per one rolling stand is
increased as compared with the case where the two-roll mandrel mill
is used.
[0005] However, the increase in the working ratio of pipe material
per one rolling stand poses a problem that it is difficult for the
front edge part of pipe material to bite stably (to secure the
roll-biting property). In particular, in the case where the
three-roll mandrel mill is used, the change in roll diameter of
rolling roll is smaller (the difference between the roll diameter
of a groove bottom part and the roll diameter of a flange part is
smaller) than the case where the two-roll mandrel mill is used.
Therefore, it is more difficult to secure the roll-biting property
of the front edge part of pipe material in the case where the
three-roll mandrel mill is used.
[0006] Also, it has been found that due to the non-steady
phenomenon at the time when the pipe material is rolled, as shown
in FIG. 4, the cross sections of the pipe edges (the front pipe
edge and the rear pipe edge) have a long circumferential length
because of being free ends, but excluding the pipe edges, the
circumferential length of the rear edge part is short partially. In
particular, in the case where the three-roll mandrel mill is used,
it is more difficult to secure the circumferential length than the
case where the two-roll mandrel mill is used (for example, refer to
JP2005-111518A, paragraph 0004). Therefore, in the case where the
three-roll mandrel mill is used, it is necessary to compensate for
a non-steady portion (a portion in which the circumferential length
is short partially) in the rear edge part.
SUMMARY OF INVENTION
[0007] The present invention has been made to solve the above
problems of prior art, and accordingly an object thereof is to
provide a rolling position adjusting device capable of restraining
poor roll-biting of the front edge part of a pipe or tube material
rolled by a three-roll mandrel mill or capable of restraining a
decrease in circumferential length of the rear edge part of the
pipe or tube material.
[0008] To solve the above problems, the present inventor conducted
studies earnestly, and resultantly found that poor roll-biting of
the front edge part of pipe or tube material can be restrained if
rolling rolls are put on standby at a position at which they are
open more as compared with the rolling time (at a position distant
from the center of pipe or tube material) before the front edge
part of pipe or tube material begins to be rolled, and the rolling
rolls are moved in the closing direction (in the direction of
approaching the center of pipe or tube material) immediately after
the front edge part of pipe or tube material has begun to be
rolled. The present invention was completed based on this new
knowledge of the present inventor.
[0009] The present invention provides a device for adjusting the
rolling positions of rolling rolls disposed on at least one rolling
stand constituting a three-roll mandrel mill, the device
comprising: a pressing-down device for moving the rolling rolls in
the rolling direction; and a control unit for controlling the
pressing-down device, wherein immediately after a front edge part
of a pipe or tube material has begun to be rolled by the rolling
rolls, the control unit controls the pressing-down device to move
the rolling rolls in the closing direction.
[0010] Preferably, the control unit moves the rolling rolls in the
closing direction at a speed of 16 millimeters per second or higher
by using the pressing-down device.
[0011] According to the above-described preferred configuration,
the yield of the front edge part of pipe or tube material can be
increased.
[0012] The present invention also provides a method for
manufacturing seamless pipes or tubes, wherein a three-roll mandrel
mill that adopts the device for adjusting the rolling positions of
rolling rolls described above is used.
[0013] Also, to solve the above problems, the present inventor
conducted studies earnestly, and resultantly found that a decrease
in circumferential length of the rear edge part of pipe or tube
material can be restrained if the rolling rolls are moved in the
closing direction (in the direction of approaching the center of
pipe or tube material) beyond the rolling position at the time when
the central part of pipe or tube material is rolled immediately
after the rear edge part of pipe or tube material has begun to be
rolled. The present invention was completed based on this new
knowledge of the present inventor.
[0014] The present invention provides a device for adjusting the
rolling positions of rolling rolls disposed on at least one rolling
stand constituting a three-roll mandrel mill, the device
comprising: a pressing-down device for moving the rolling rolls in
the rolling direction; and a control unit for controlling the
pressing-down device, wherein immediately after a rear edge part of
a pipe or tube material has begun to be rolled by the rolling
rolls, the control unit controls the pressing-down device to move
the rolling rolls in the closing direction.
[0015] Preferably, the control unit moves the rolling rolls in the
closing direction at a speed of 16 millimeters per second or higher
by using the pressing-down device.
[0016] According to the above-described preferred configuration,
the yield of the rear edge part of pipe or tube material can be
increased while the decrease in circumferential length of the rear
edge part is restrained.
[0017] The present invention also provides a method for
manufacturing seamless pipes or tubes, wherein a three-roll mandrel
mill that adopts the device for adjusting the rolling positions of
rolling rolls described above is used.
[0018] According to the present invention, poor roll-biting of the
front edge part of pipe or tube material rolled by the three-roll
mandrel mill can be restrained. Also, according to the present
invention, the decrease in circumferential length of the rear edge
part of pipe or tube material can be restrained.
BRIEF DESCRIPTION OF DRAWINGS
[0019] FIG. 1 is a schematic view showing a general configuration
of a rolling position adjusting device for rolling rolls
constituting a three-roll mandrel mill in accordance with one
embodiment of the present invention.
[0020] FIG. 2 is a graph schematically showing one example of a
change in rolling reduction of rolling rolls R1 at the time when
the front edge part of a pipe material T is rolled by a first
rolling stand (a rolling stand on which the rolling rolls R1 are
disposed) shown in FIG. 1.
[0021] FIG. 3 is a graph schematically showing one example of a
change in rolling reduction of rolling rolls R1 at the time when
the rear edge part of a pipe material T is rolled by a first
rolling stand (a rolling stand on which the rolling rolls R1 are
disposed) shown in FIG. 1.
[0022] FIG. 4 is a graph showing one example of a change in
circumferential length of a pipe material with respect to
longitudinal direction of the pipe material, which is caused by a
non-steady phenomenon when the pipe material is rolled by a mandrel
mill.
DESCRIPTION OF EMBODIMENTS
[0023] One embodiment of the present invention will now be
described with reference to the accompanying drawings as
appropriate.
[0024] FIG. 1 is a schematic view showing a general configuration
of a rolling position adjusting device for rolling rolls
constituting a three-roll mandrel mill in accordance with one
embodiment of the present invention.
[0025] As shown in FIG. 1, a rolling position adjusting device 100
in accordance with this embodiment is used in a three-roll mandrel
mill consisting of a total of six rolling stands on each of which
three rolling rolls are disposed to elongation-roll the outside
surface of a pipe material T in the state in which a mandrel bar B
is inserted into the pipe material T in a spit form. Describing
more specifically, the rolling position adjusting device 100 in
accordance with this embodiment is configured so as to be capable
of adjusting the rolling positions of the rolling rolls R1 to R6
disposed on the respective rolling stands of the mandrel mill. For
convenience, in FIG. 1, the rolling rolls R1 to R6 are shown so
that two rolling rolls are disposed on each of the rolling stands.
Actually, however, there are three rolling rolls R1, three rolling
rolls R2, and so on up to R6 disposed so that the angle between the
rolling directions is 120 degrees.
[0026] The rolling position adjusting device 100 has pressing-down
devices 1 (P1 to P6) for moving the rolling rolls R1 to R6 in the
rolling direction respectively, and a control unit 2 for
controlling the pressing-down devices 1.
[0027] The pressing-down device 1 is configured by a hydraulic
cylinder or the like.
[0028] The control unit 2 receives detection signals sent from a
detector (not shown), which is provided on the entrance side of
mandrel mill to detect the front edge or the rear edge of the pipe
material T, and detection signals sent from a sensor (for example,
a pulse generator attached to a conveyance roller for the pipe
material T) for detecting the conveyance speed of the pipe material
T. Based on the received detection signals, the control unit 2
detects the timing of roll-biting of the front edge of the pipe
material T with the rolling stand or the timing of withdrawal of
the rear edge of the pipe material T from the rolling stand.
[0029] Immediately after the front edge part of the pipe material T
has begun to be rolled by the rolling rolls disposed on at least
one rolling stand of the rolling rolls R1 to R6, the control unit 2
controls the pressing-down device 1 to move the concerned rolling
rolls in the closing direction.
[0030] FIG. 2 is a graph schematically showing one example of a
change in rolling reduction of the rolling rolls R1 at the time
when the front edge part of the pipe material T is rolled by a
first rolling stand (a rolling stand on which the rolling rolls R1
are disposed). As shown in FIG. 2, for example, in the front edge
part of the pipe material T, the rolling rolls R1 are closed so
that the rolling reduction changes from 0 mm to 8 mm immediately
after the start of rolling. Also, it is assumed that the length of
the pipe material T is 10 m, and a length region of 5% from the
front edge of the pipe material T (that is, a range of 500 mm from
the front edge) may have poor wall thickness. That is, it is
assumed that the rolling rolls R1 may be closed so that the rolling
reduction is 8 mm in the period from the time when the front edge
of the pipe material T bites onto the first rolling stand to the
time when it passes through a position of 500 mm. If the conveyance
speed of the pipe material T is, for example, 1 m/sec, 0.5 sec
elapses in the period from the time when the front edge of the pipe
material T bites onto the first rolling stand to the time when it
passes through a position of 500 mm. In order to make the rolling
reduction 8 mm in the time period of 0.5 sec (that is, to move the
rolling rolls R1 through 8 mm in the closing direction), the
rolling rolls R1 must be moved in the closing direction at a speed
of 16 mm/sec. As in the example shown in FIG. 2, in order to
increase the yield of the front edge part of the pipe material T
(to reduce the length region having poor wall thickness to 5% or
less), it is preferable that the control unit 2 move the rolling
rolls R1 in the closing direction at a speed of 16 mm/sec or higher
by using the pressing-down device 1. In the case where the length
region having poor wall thickness may be longer than 5% from the
front edge of the pipe material T, for example, in the case where
the length region having poor wall thickness may be 6%, the rolling
rolls R1 may be moved in the closing direction at a speed of 13
mm/sec or higher.
[0031] Poor roll-biting does not necessarily occur on the first
rolling stand only. The movement of the rolling rolls R1 in the
closing direction immediately after the start of rolling of the
front edge part of the pipe material T on the first rolling stand
substantially reduces the rolling reduction of the front edge part
on the first rolling stand. If the rolling reduction of the front
edge part is decreased as described above on the first rolling
stand, the rolling reductions on the second and subsequent rolling
stands increase. Therefore, it is desirable to control the
pressing-down devices 1 on the second and subsequent rolling stands
as necessary as on the above-described first rolling stand. For
example, when the front edge part of the pipe material T is rolled
on the sixth rolling stand shown in FIG. 1 (the rolling stand on
which the rolling rolls R6 are disposed), the rolling reduction of
the rolling rolls R6 is changed as described below. For example, in
the front edge part of the pipe material T, the rolling rolls R6
are closed so that the rolling reduction changes from 0 mm to 0.8
mm immediately after the start of rolling. Also, it is assumed that
the length after rolling of the pipe material T is 15 m, and a
length region of 1% from the front edge of the pipe material T
(that is, a range of 150 mm from the front edge) may have poor wall
thickness. That is, it is assumed that the rolling rolls R6 may be
closed so that the rolling reduction becomes 0.8 mm in the period
from the time when the front edge of the pipe material T bites onto
the sixth rolling stand to the time when it passes through a
position of 150 mm. If the conveyance speed after rolling of the
pipe material T is, for example, 3 m/sec, 0.05 sec elapses in the
period from the time when the front edge of the pipe material T
bites onto the sixth rolling stand to the time when it passes
through a position of 150 mm. In order to make the rolling
reduction 0.8 mm in the time period of 0.05 sec (that is, to move
the rolling rolls R6 through 0.8 mm in the closing direction), the
rolling rolls R6 must be moved in the closing direction at a speed
of 16 mm/sec. In order to increase the yield of the front edge part
of the pipe material T so as to reduce the length region having
poor wall thickness to 1% or less, it is preferable that the
control unit 2 move the rolling rolls R6 in the closing direction
at a speed of 16 mm/sec or higher by using the pressing-down device
1.
[0032] Immediately after the rear edge part of the pipe material T
has begun to be rolled by the rolling rolls disposed on at least
one rolling stand of the rolling rolls R1 to R6, the control unit 2
controls the pressing-down device 1 to move the concerned rolling
rolls in the closing direction.
[0033] FIG. 3 is a graph schematically showing one example of a
change in rolling reduction of the rolling rolls R1 at the time
when the rear edge part of the pipe material T is rolled by the
first rolling stand. As shown in FIG. 3, for example, in the rear
edge part of the pipe material T, the rolling rolls R1 are closed
so that the rolling reduction increases by 4 mm immediately after
the start of rolling. It is assumed that the length of the pipe
material T is 10 m, and a length region of 2.5% from the first
position of the rear edge part of the pipe material T (that is, a
range of 250 mm from the first position of the rear edge part) may
have poor wall thickness. That is, it is assumed that the rolling
rolls R1 may be closed so that the rolling reduction becomes 4 mm
in the period from the time when the first position of the rear
edge part of the pipe material T bites onto the first rolling stand
to the time when it passes through a position of 250 mm. If the
conveyance speed of the pipe material T is, for example, 1 m/sec,
0.25 sec elapses in the period from the time when the first
position of the rear edge part of the pipe material T bites onto
the first rolling stand to the time when it passes through a
position of 250 mm. In order to make the rolling reduction 4 mm in
the time period of 0.25 sec (that is, to move the rolling rolls R1
through 4 mm in the closing direction), the rolling rolls R1 must
be moved in the closing direction at a speed of 16 mm/sec. As in
the example shown in FIG. 2, in order to increase the yield of the
rear edge part of the pipe material T (to reduce the length region
having poor wall thickness to 2.5% or less), it is preferable that
the control unit 2 move the rolling rolls R1 in the closing
direction at a speed of 16 mm/sec or higher by using the
pressing-down device 1. In the case where the length region having
poor wall thickness may be longer than 2.5% from the first position
of the rear edge part of the pipe material T, for example, in the
case where the length region having poor wall thickness may be 3%,
the rolling rolls R1 may be moved in the closing direction at a
speed of 13 mm/sec or higher.
[0034] Difficulty in securing the circumferential length does not
necessarily arise on the first rolling stand only. Rather, in order
to draw the mandrel bar B out of the pipe material T once rolling
is completed in the mandrel mill, it is important to secure the
circumferential length of the pipe material T after rolling on the
final rolling stand. Therefore, it is desirable to control the
pressing-down devices 1 on the second and subsequent rolling
stands, especially on the final rolling stand, as necessary as on
the above-described first rolling stand. Considering the equipment
investment cost, the pressing-down device 1 may be controlled on
the fifth and sixth rolling stands only. For example, when the rear
edge part of the pipe material T is rolled on the sixth rolling
stand shown in FIG. 1 (the rolling stand on which the rolling rolls
R6 are disposed), the rolling reduction of the rolling rolls R6 is
changed as described below. For example, in the rear edge part of
the pipe material T, the rolling rolls R6 are closed so that the
rolling reduction increases by 2 mm immediately after the start of
rolling. It is assumed that the length after rolling of the pipe
material T is 15 m, and a length region of 2.5% from the first
position of the rear edge part of the pipe material T (that is, a
range of 375 mm from the first position of the rear edge part) may
have poor wall thickness. That is, it is assumed that the rolling
rolls R6 may be closed so that the rolling reduction becomes 2 mm
in the period from the time when the first position of the rear
edge part of the pipe material T bites onto the sixth rolling stand
to the time when it passes through a position of 375 mm. If the
conveyance speed of the pipe material T is, for example, 3 m/sec,
0.125 sec elapses in the period from the time when the first
position of the rear edge part of the pipe material T bites onto
the sixth rolling stand to the time when it passes through a
position of 375 mm. In order to make the rolling reduction 2 mm in
the time period of 0.125 sec (that is, to move the rolling rolls R6
through 2 mm in the closing direction), the rolling rolls R6 must
be moved in the closing direction at a speed of 16 mm/sec. In order
to increase the yield of the rear edge part of the pipe material T
(to reduce the length region having poor wall thickness to 2.5% or
less), it is preferable that the control unit 2 move the rolling
rolls R6 in the closing direction at a speed of 16 mm/sec or higher
by using the pressing-down device 1.
* * * * *