U.S. patent application number 16/500294 was filed with the patent office on 2020-02-27 for method of cooling main roll for ring rolling and method of manufacturing ring rolled body.
The applicant listed for this patent is HITACHI METALS, LTD.. Invention is credited to Tomoyoshi KIWAKE, Takanori MATSUI, Takuya MURAI.
Application Number | 20200061686 16/500294 |
Document ID | / |
Family ID | 63712982 |
Filed Date | 2020-02-27 |
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United States Patent
Application |
20200061686 |
Kind Code |
A1 |
MURAI; Takuya ; et
al. |
February 27, 2020 |
METHOD OF COOLING MAIN ROLL FOR RING ROLLING AND METHOD OF
MANUFACTURING RING ROLLED BODY
Abstract
In a method of cooling a main roll, strength of a shaft and a
peripheral portion thereof of the main roll is sufficiently
secured, maintenance of the main roll is facilitated, and the shaft
and the peripheral portion thereof of the main roll are efficiently
cooled. In a method of manufacturing a ring rolled body, a
high-quality ring rolled body is produced. The present invention
relates to a method of cooing a main roll 1 for ring rolling in a
state in which one side, in the rotation axis direction, of the
main roll 1 faces upward, and relates to a method of manufacturing
a ring rolled body, including the cooling method. In the cooling
method, the shaft 11 is cooled by injecting a liquid W into a
receiving part 13, 17 which is recessed from an upper end surface
12c of a die 12 of the main roll 1 facing the one side in the
rotation axis direction and surrounds the shaft 11 of the main roll
1. In the method of manufacturing a ring rolled body, a ring rolled
body is manufactured by heating the die 12 by an induction heating
mechanism 6 and cooling the shaft 11 by the cooling method, and
further, reducing a ring material M between the main roll 1 and the
mandrel 2.
Inventors: |
MURAI; Takuya; (Tokyo,
JP) ; MATSUI; Takanori; (Tokyo, JP) ; KIWAKE;
Tomoyoshi; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HITACHI METALS, LTD. |
Tokyo |
|
JP |
|
|
Family ID: |
63712982 |
Appl. No.: |
16/500294 |
Filed: |
March 28, 2018 |
PCT Filed: |
March 28, 2018 |
PCT NO: |
PCT/JP2018/012814 |
371 Date: |
October 2, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B21B 27/10 20130101;
B21B 5/00 20130101; B21B 27/02 20130101; B21J 13/02 20130101; B21H
1/06 20130101 |
International
Class: |
B21B 27/10 20060101
B21B027/10; B21H 1/06 20060101 B21H001/06 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 4, 2017 |
JP |
2017-074512 |
Claims
1. A method of cooling a main roll, the main roll including a shaft
extending along a rotation axis of the main roll and a die disposed
so as to surround the shaft, the main roll being used for ring
rolling, the main roll being cooled in a state in which one side in
a rotation axis direction faces upward, the method comprising:
cooling the shaft of the main roll by injecting a liquid into a
receiving part, the receiving part being recessed from an upper end
surface of the die of the main roll facing the one side in the
rotation axis direction, the receiving part surrounding the shaft
of the main roll.
2. The method of cooling the main roll according to claim 1,
wherein the liquid injected into the receiving part, flows through
a plurality of liquid passages which extend from the receiving part
to the other side in the rotation axis direction and are spaced
apart from each other in a circumferential direction of the main
roll, in the die.
3. The method of cooling the main roll according to claim 2,
wherein the liquid flowing into at least one liquid passage among
the plurality of the liquid passages, is discharged to an outside
of the main roll from an outlet of the at least one liquid passage
which opens at a lower end surface of the die located on the other
side in the rotation axis direction.
4. The method of cooling the main roll according to claim 2,
wherein the liquid flowing into at least one liquid passage among
the plurality of the liquid passages, is stored on and above a
bottom formed on the at least one liquid passage having a blind
hole shape.
5. A method of manufacturing a ring rolled body to produce the ring
rolled body by rolling a ring material, the method comprising: a
temperature control step of heating a die of a main roll by a
heating mechanism, and cooling a shaft of the main roll by the
method of cooling the main roll, according to claim 1; and a
rolling step of performing reduction between an inner periphery and
an outer periphery of the ring material by the main roll on which
temperature control is performed in the temperature control step,
and by a mandrel.
Description
TECHNICAL FIELD
[0001] The present invention relates to a method of cooling a main
roll to be used for ring rolling. Furthermore, the present
invention relates to a method of manufacturing a ring rolled body,
in which to produce a rolled body which is formed in a
substantially ring shape (hereinafter referred to as a "ring rolled
body"), a die of a main roll is heated, the shaft of the main roll
is cooled by the cooling method, and furthermore, a material in a
substantially ring shape (hereinafter referred to as a "ring
material") is reduced in the radial direction thereof between the
main roll and a mandrel.
BACKGROUND ART
[0002] For gears, rotary bodies of a rotary mechanism, and the
like, which are used in various industrial fields, a component
formed in a substantially ring shape (hereinafter, referred to as
"ring component"), is used. In most cases, a ring component is
produced by processing a ring rolled body. A ring rolled body is
produced by performing ring rolling on a ring material. For ring
rolling, a rolling mill, such as a ring rolling mill, is used.
[0003] A rolling mill is provided with forming rolls for reducing a
ring material to form a ring rolled body. For example, forming
rolls include a main roll and a mandrel to reduce a ring material
between the inner and outer peripheries of the ring material.
Forming rolls are exposed to high-temperature environments during
ring rolling, in particular, during hot ring rolling. Therefore, to
protect the forming rolls, precise control of the temperature of
the forming rolls is necessary, and to enhance the quality of a
ring rolled body produced with use of the forming rolls, cooling of
the forming rolls may be required. Therefore, various techniques of
cooling forming rolls have been proposed.
[0004] As an example of cooling techniques, a technique in which a
cooling solvent, such as cooling water, is sprayed to a processed
part surrounding the rotary shaft in a forming roll, has been
proposed. As another example of a cooling technique, a technique in
which a water passage extending from one end to the other end, in
the rotary axis direction, of a forming roll along the rotary shaft
of the forming roll, is provided, and cooling water is flowed
through the water passage, has been proposed (for example, see
Patent Literatures 1 and 2).
CITATION LIST
Patent Literature
[0005] [Patent Literature 1] JP S58-025834 A
[0006] [Patent Literature 2] JP S54-101757 A
SUMMARY OF INVENTION
Technical Problem
[0007] However, in the ring rolling such as an example of the
cooling technique described above, since a cooling medium is
sprayed to the processed part of the forming roll, which is in
contact with a ring material, the temperature of the processed part
of the forming roll may be decreased. Therefore, in the ring
rolling, defects, such as cracking of a ring material which is in
contact with the processed part of the forming roll, and defective
deformation may be caused. In particular, in the case in which a
ring material is made of a metallic material being hard to be
processed, such as Ni-based superalloy, Co-based alloy and/or the
like, the probability increases that defects will occur in the ring
material. The aforementioned example of the cooling technique also
involves a problem that in the forming roll, the rotary shaft and
the peripheral portion thereof are hardly cooled.
[0008] In addition, in another example of a cooling technique, the
rotary shaft and a peripheral portion thereof of a forming roll are
provided with a mechanism of rotating the forming roll, in addition
to a mechanism of allowing cooling water to flow through a water
passage. The structure of the rolling mill becomes complicated by
these mechanisms provided. Consequently, it may be difficult to
secure the strength of the main roll of the rolling mill, in
particular, the rotary shaft and the peripheral portion thereof of
the main roll. It may also be difficult to perform maintenance of
the rolling mill.
[0009] In particular, in the case of applying the one example and
the another example of the cooling techniques to the main roll of a
ring rolling mill, the above problems are remarkable. Therefore, in
the method of cooling a main roll of a ring rolling mill, it is
desirable to facilitate the maintenance of the main roll and
efficiently cool the shaft and the peripheral portion thereof of
the main roll, while sufficiently securing the strength of the
shaft and the peripheral portion thereof of the main roll.
Furthermore, in the method of manufacturing a ring rolled body, it
is desirable to produce a high-quality ring rolled body by using a
main roll in which appropriate temperature control is practiced so
as to efficiently cool the shaft and the peripheral portion thereof
of the main roll while heating a die of the main roll, in
particular, a processed part of the die being in contact with a
ring material.
Solution to Problem
[0010] To solve the problems, a method of cooling a main roll,
according to one aspect of the present invention, is a method of
cooling a main roll which includes a shaft extending along the
rotation axis of the main roll, and a die disposed so as to
surround the shaft, and the main roll is used for ring rolling. The
main roll is cooled in a state in which one side in the rotation
axis direction thereof faces upward. The method includes cooling
the shaft of the main roll by injecting a liquid into a receiving
part which is recessed from an upper end surface of the die of the
main roll facing the one side in the rotation axis direction and
surrounds the shaft of the main roll. The method also includes
cooling the shaft and the peripheral portion thereof of the main
roll.
[0011] A method of manufacturing a ring rolled body, according to
one aspect of the present invention, is a method of manufacturing a
ring rolled body to produce the ring rolled body by rolling a ring
material. The method includes: a temperature control step of
heating a die of a main roll by a heating mechanism, and cooling a
shaft of the main roll by the method of cooling the main roll,
according to the one aspect of the present invention; and a rolling
step of performing reduction between the inner periphery and the
outer periphery of the ring material by the main roll on which
temperature control is performed in the temperature control step,
and by a mandrel.
Advantageous Effects of Invention
[0012] In the method of cooling a main roll, according to one
aspect of the present invention, the strength of the shaft and the
peripheral portion thereof of the main roll can be sufficiently
secured, the maintenance of the main roll can be facilitated, and
the shaft and the peripheral portion thereof of the main roll can
be efficiently cooled. Furthermore, in the method of manufacturing
a ring rolled body, according to one aspect of the present
invention, a high-quality ring rolled body can be produced by use
of a main roll in which appropriate temperature control is
practiced so as to efficiently cool the shaft and the peripheral
portion thereof of the main roll while heating the die of the main
roll, in particular, a processed part of the die being in contact
with the ring material.
BRIEF DESCRIPTION OF DRAWINGS
[0013] FIG. 1 is a perspective view schematically showing a rolling
mill to be used in a method of cooling a main roll and a method of
manufacturing a ring rolled body, according to a First Embodiment
of the present invention.
[0014] FIG. 2 is a plan view schematically showing a shaft and a
die of a main roll in the rolling mill, according to the First
Embodiment of the present invention.
[0015] FIG. 3 is a cross-sectional view taken along line A-A of
FIG. 2.
[0016] FIG. 4 is a flowchart for explaining a method of cooling a
main roll, according to the First Embodiment of the present
invention.
[0017] FIG. 5 is a flowchart for explaining a method of
manufacturing a ring rolled body, according to the First Embodiment
of the present invention.
[0018] FIG. 6 is a cross-sectional view schematically showing a
shaft and a die of a main roll, in a state of being cut along line
A-A of FIG. 2, according to a Second Embodiment of the present
invention.
[0019] FIG. 7 is a cross-sectional view schematically showing a
shaft and a die of a main roll, in a state of being cut along line
A-A of FIG. 2, according to a Third Embodiment of the present
invention.
DESCRIPTION OF EMBODIMENTS
[0020] Methods of cooling a main roll, methods of manufacturing a
rolled body in a substantially ring shape (hereinafter, referred to
as a "ring rolled body"), and rolling mills, according to First to
Fourth Embodiments of the present invention, will be described
below. Note that in a method of cooling a main roll, a shaft and
its peripheral portion of a main roll of a rolling mill are mainly
cooled. Furthermore, in a method of manufacturing a ring rolled
body, while a die of a main roll, in particular, a processed part
on the outer peripheral surface of a die being in contact with a
material in a substantially ring shape (hereinafter, referred to as
a "ring material") are heated, the shaft and its peripheral portion
of the main roll are mainly cooled by the cooling method, and
furthermore, the ring material is reduced between the main roll and
a mandrel. Note that the method of cooling a main roll is also
applicable to a method of manufacturing a ring rolled body other
than those of the First to Fourth Embodiments of the present
invention.
[0021] In the First to Fourth Embodiments of the present invention,
a ring rolled body is used for producing a component in a
substantially ring shape (hereinafter, referred to as a "ring
component"). As an example, a ring component may be a gear, a
rotary body of a rotary mechanism, or the like, to be used in
various industrial fields. A ring component is preferably one which
needs strict dimension control, in particular, for gas turbines,
steam turbines, turbine disks used in a jet engine of an aircraft,
or the like. As an example, it is preferable that the maximum
diameter of the outer periphery of a ring rolled body be equal to
or greater than approximately 600 mm but equal to or less than
approximately 2000 mm. However, the present invention is not
limited thereto. The maximum diameter of the outer periphery of the
ring rolled body may be less than approximately 600 mm but greater
than approximately 2000 mm, depending on a ring component to be
produced with use of the ring rolled body.
[0022] Furthermore, in the First to Fourth Embodiments of the
present invention, a ring rolled body is shaped by applying ring
rolling to a ring material. In particular, it is preferable that a
ring material be produced using a metal material having excellent
high-temperature strength, high-temperature toughness, and/or the
like. For example, it is preferable that the ring material be
produced using a metal material selected from Ni-based alloys,
Fe-based alloys, Co-based alloys, Ti-based alloys, and the like
which are excellent in high-temperature strength, high-temperature
toughness, and/or the like.
First Embodiment
[0023] A method of cooling a main roll, a method of manufacturing a
ring rolled body, and a rolling mill, according to a First
Embodiment of the present invention, will be described.
[0024] Regarding Rolling Mill
[0025] First, with reference to FIG. 1, a rolling mill to be used
in a method of cooling a main roll 1 and a method of manufacturing
a ring rolled body, according to the present Embodiment, will be
described. A rolling mill is configured such that a ring material M
formed so as to be substantially rotationally symmetrical with
reference to a central axis C, is attachable and detachable. The
rolling mill is also configured such that ring rolling is performed
on the ring material M attached thereto.
[0026] Specifically, the rolling mill includes a main roll 1 and a
mandrel 2 as described above. The main roll 1 and the mandrel 2
contact an outer peripheral surface m1 and an inner peripheral
surface m2 of the ring material M, respectively, and reduce the
ring material M in the radial direction thereof (hereinafter
referred to as a "ring radial direction") between them. The rolling
mill also includes a pair of axial rolls 3, 4. The pair of axial
rolls 3, 4 contacts an upper end surface m3 and a lower end surface
m4, in a direction of the central axis C, of the ring material M
(hereinafter referred to as a "ring axial direction"), and reduces
the ring material M in the ring axial direction between them.
[0027] The rolling mill also includes a liquid supply mechanism 5
for supplying water W to cool the main roll 1. As an example, it is
preferable that the temperature of the water W is a normal
temperature. The rolling mill also includes an induction heating
mechanism 6 configured so as to inductively heat the main roll 1.
In ring rolling, the ring material M comes into contact with the
main roll 1 which is inductively heated by the induction heating
mechanism 6.
[0028] However, the present invention is not limited thereto. The
rolling mill may be configured as described below. The rolling mill
may be configured so as to not include a pair of axial rolls. The
liquid supply mechanism may supply liquid other than water, if it
is possible to cool the main roll. In particular, the liquid
preferably has flame resistance and high fluidity. The liquid may
be silicone oil and/or the like, for example. A rolling mill may
include a heating mechanism other than an induction heating
mechanism, if it is possible to heat the main roll. A heating
mechanism may be a gas burner and/or the like, for example.
[0029] Regarding Main Roll and Mandrel
[0030] With reference to FIG. 1, the main roll 1 and the mandrel 2
will be described. The main roll 1 and the mandrel 2 are rotatable
about rotation axes 1a, 2a, respectively. Each of the main roll 1
and the mandrel 2 is arranged such that one side in the direction
of the rotation axis 1a, 2a (hereinafter referred to as a "rotation
axis direction" for each of the main roll 1 and mandrel 2) faces
upward.
[0031] Each of the main roll 1 and the mandrel 2 has a shaft 11, 21
extending along the rotation axis 1a, 2a thereof, and a die 12, 22
surrounding the shaft 11, 21. The shaft 11, 21 and the die 12, 22
are different members. The die 12, 22 is attached to the shaft 11,
21. However, the present invention is not limited thereto. In at
least one of the main roll and the mandrel, the shaft and the die
may be integrated.
[0032] Each of the dies 12, 22 of the main roll 1 and mandrel 2 has
an outer peripheral surface 12a, 22a formed in substantially
rotationally symmetrical with reference to the rotation axis 1a,
2a. The outer peripheral surfaces 12a, 22a contact the outer
peripheral surface m1 and the inner peripheral surface m2 of the
ring material M, respectively. Each of the outer peripheral
surfaces 12a, 22a of the dies 12, 22 in the main roll 1 and the
mandrel 2 has a shape corresponding to the shape of a ring rolled
body produced. As an example, the ring material M shown in FIG. 1,
is formed to have one protruded portion m5 which protrudes from the
outer peripheral surface m1 and extends along the circumferential
direction (hereinafter referred to as a "ring circumferential
direction") of the ring material M, and the outer peripheral
surface 12a of the die 12 of the main roll 1 is formed to have one
recessed portion 12b which corresponds to the one protruded portion
m5 and extends along the circumferential direction of the main roll
1. However, the present invention is not limited thereto. The outer
peripheral surface of the ring material may be formed in a shape
other than that having one protruded portion, and the outer
peripheral surface of the die of the main roll may be formed
corresponding to this outer peripheral surface of the ring
material.
[0033] It is preferable that at least one of the main roll 1 and
mandrel 2 be rotationally driven by a drive mechanism (not shown).
In that case, the drive mechanism may be mounted on at least one of
the shafts 11, 21 of the main roll 1 and the mandrel 2. The
rotational speed of the main roll 1 and the mandrel 2 may be
controllable as required. In particular, it is preferable that only
the main roll 1 be rotationally driven. The main roll 1 and the
mandrel 2 may also be movable in the ring radial direction as the
ring material M is enlarged in the ring diameter direction.
[0034] The ring material M is reduced in the ring radial direction
between the outer peripheral surfaces 12a, 22a of the dies 12, 22
of the main roll 1 and the mandrel 2, in a state of rotating in the
ring circumferential direction along with the rotation of the main
roll 1 and the mandrel 2. Note that in the method of manufacturing
a ring rolled body described below, description will be in the case
in which the main roll 1 rotates to one side (indicated by arrow
R1) in the rotational direction thereof and the mandrel 2 rotates
to one side (indicated by arrow R2) in the rotational direction
thereof, and along with this rotation, the ring material M rotates
toward one side of the ring circumferential direction (indicated by
arrow F).
[0035] Furthermore, the main roll 1 may have a size which can be
heated by the induction heating mechanism 6 but is difficult to be
heated by a heating furnace, a gas burner, and/or the like. In
particular, it is preferable that the maximum diameter of the outer
peripheral surface 12a of the die 12 of the main roll 1 be
approximately 1000 mm or greater. However, the present invention is
not limited thereto. The maximum diameter of the outer peripheral
surface of the die in the main roll may be less than approximately
1000 mm, if the main roll can be heated appropriately.
[0036] Cooling Structure of Main Roll
[0037] With reference to FIGS. 2 and 3, a cooling structure of the
main roll 1 will be described. The die 12 of the main roll 1 has a
receiving part 13 which is recessed downward from the upper end
surface 12c. The receiving part 13 opens at the upper end surface
12c of the die 12, and extends in the circumferential direction of
the main roll 1 so as to surround the shaft 11. The receiving part
13 receives water W supplied from the liquid supply mechanism
5.
[0038] The die 12 of the main roll 1 also includes a plurality of
liquid passages 14 extending from the receiving part 13 toward the
other side of the rotation axis direction. The liquid passages 14
are spaced apart from one another (each other) in the
circumferential direction of the main roll 1. As an example, the
die 12 shown in FIGS. 2 and 3, has four liquid passages 14.
However, the present invention is not limited thereto. The die can
have two or more liquid passages. In particular, it is preferable
that the die have three or more liquid passages.
[0039] Furthermore, the die 12 has a mounting hole 15 which
penetrates so as to allow the shaft 11 to be inserted. The mounting
hole 15 extends from a bottom surface 13b of the receiving part 13
to the lower end surface 12d of the die 12 along the rotation axis
1a of the main roll 1. The shaft 11 is mounted on the die 12 in a
state of being inserted in the mounting hole 15.
[0040] In the cooling structure of the main roll 1, the receiving
part 13 has: an opening edge 13a located at the upper end surface
12c of the die 12; the bottom surface 13b facing the opening edge
13a; and an inner peripheral surface 13c extending between the
opening edge 13a and the outer peripheral edge of the bottom
surface 13b.
[0041] When considering prevention of a temperature drop in the
processed part on the outer peripheral surface 12a of the die 12
which contacts the ring material M, and prevention of a decrease in
the strength of the die 12, it is preferable that the bottom
surface 13b of the receiving part 13 be positioned above the
processed part of the die 12. As an example, when the main roll 1
rotates, the liquid, such as water W in the receiving part 13 is
applied with centrifugal force. Therefore, the bottom surface 13b
is preferably formed so as to have a depth in the receiving part 13
in which the liquid can be held within the receiving part 13. The
bottom surface 13b may be formed in a substantially flat shape
along the horizontal direction.
[0042] Furthermore, when considering prevention of a temperature
drop in the outer peripheral surface 12a of the die 12, and
prevention of a decrease in the strength of the peripheral portion
of the shaft 11 in the die 12, it is preferable that the maximum
distance from the rotation axis 1a of the main roll 1 to the inner
peripheral surface 13c of the receiving part 13 be equal to or less
than 3/4 of the minimum distance from the rotation axis 1a of the
main roll 1 to the outer peripheral surface 12a of the die 12, and
more preferably, it be equal to or less than 1/2 of the minimum
distance. The inner peripheral surface 13c is formed along the
vertical direction. However, the present invention is not limited
thereto. The inner peripheral surface may be inclined against the
vertical direction. For example, the inner peripheral surface may
be formed so as to taper off from the bottom surface of the
receiving part toward the opening edge.
[0043] Furthermore, in the cooling structure of the main roll 1,
each of the liquid passages 14 has: an inlet 14a which opens at the
receiving part 13; and an outlet 14b which opens at the lower end
surface 12d of the die 12. Each liquid passage 14 may also
communicate with the mounting hole 15 in the radial direction of
the main roll 1. In particular, it is preferable that each liquid
passage 14 be formed so as to be recessed from the inner peripheral
surface 15a of the mounting hole 15. It is also preferable that
each liquid passage 14 extend along the shaft 11. However, the
present invention is not limited thereto. At least one of the
liquid passages may be spaced apart from the mounting hole 15 in
the radial direction of the main roll.
[0044] Regarding Liquid Supply Mechanism
[0045] With reference to FIG. 1, the liquid supply mechanism 5 of
the rolling mill will be described. The liquid supply mechanism 5
includes: a supply pipe 51 in which water W can pass through the
supply pipe 51; and a valve 52 provided to the supply pipe 51. At
the distal end of the supply pipe 51, a supply port 51a for
supplying water W to the receiving part 13, is formed. The supply
port 51a is positioned above the receiving part 13. The valve 52 is
openable and closable so as to switch the state between a state in
which the water W flows out of the supply port 51a, and a state in
which outflow of the water W is stopped. In particular, it is
preferable that the valve 52 be adjustable for the opening and
closing amount so as to adjust the supply amount of the water W
from the supply port 51a.
[0046] The liquid supply mechanism 5 also has a temperature
detection unit 53 capable of detecting the temperature of the
receiving part 13 of the main roll 1. It is preferable that the
temperature detection unit 53 detect the temperature of the
receiving part 13 in a non-contact manner. As an example, the
temperature detection unit 53 may be a radiation thermometer.
However, the present invention is not limited thereto. The
temperature detection unit may be able to detect the temperature of
the water discharged from the outlet of the die.
[0047] The liquid supply mechanism 5 also includes a control unit
54 which enables control of supply of the water W from the supply
pipe 51 to the receiving part 13. The control unit 54 is
electrically connected to the valve 52 and the temperature
detection unit 53. The control unit 54 receives a temperature
detection value of the receiving part 13 from the temperature
detection unit 53. The control unit 54 also controls open and close
of the valve 52 according to the temperature detection value. In
particular, it is preferable that the control unit 54 be able to
control the opening and closing amount of the valve 52. As an
example, the control unit 54 may be a control unit including an
electric component, such as a CPU, an electric circuit, and/or the
like.
[0048] Regarding Induction Heating Mechanism
[0049] The induction heating mechanism 6 of the rolling mill will
be described. Although not shown in particular, the induction
heating mechanism 6 includes an induction heating coil having a
winding wound around at least once. In this induction heating
mechanism 6, a line of magnetic flux for induction heating is
generated when an alternate current flows through the winding of
the induction heating coil.
[0050] As shown in FIG. 1, the induction heating mechanism 6 is
disposed around the outer peripheral surface 12a of the die 12 in
the main roll 1 so as to inductively heat the processed part
(including the recessed part 12b) of the outer peripheral surface
12a of the die 12. In particular, it is preferable that the
induction heating mechanism 6 be placed in a region (hereinafter
referred to as a "region immediately before inner and outer
periphery reduction region") adjacent to the other side in the
rotation direction of the main roll 1, with respect to the
reduction region (hereinafter referred to as an "inner and outer
periphery reduction region") between the main roll 1 and the
mandrel 2, around the outer peripheral surface 12a of the die 12.
As an example, it is preferable that the region immediately before
inner and outer periphery reduction region be located within a
range of a length obtained by dividing the entire peripheral length
of the main roll 1 into four, from the inner and outer periphery
reduction region to the other side in the rotation direction of the
main roll 1. However, the present invention is not limited thereto.
The induction heating mechanism may inductively heat an edge-shape
contact part of the main roll, which contacts the edge-shaped part
formed on the outer peripheral surface of the ring material.
[0051] Regarding Method of Cooling Main Roll
[0052] A method of cooling the main roll 1, according to the
present Embodiment will be described with reference to FIGS. 1 and
4. First, the valve 52 is closed, and supply of the water W from
the supply pipe 51 is stopped (Step S1). A temperature detection
value of the receiving part 13 is obtained by the temperature
sensor 52 (Step S2). By the control unit 54, it is determined
whether or not the temperature detection value of the receiving
part 13 is greater than a pre-determined temperature upper limit
threshold (Step S3).
[0053] When the temperature detection value of the receiving part
13 is equal to or less than the temperature upper limit threshold
(NO), the process returns to the work of obtaining a temperature
detection value of the receiving part 13 by the temperature sensor
52 before the determination (Step S2). On the other hand, when the
temperature detection value of the receiving part 13 is greater
than the temperature upper limit threshold (YES), the valve 52 is
opened to supply the water W from the supply pipe 51 to the
receiving part 13 (Step S4). Note that before supplying of the
water W to the receiving part 13, pre-processing to prevent
generation of scale may be applied to the water W. Next, by the
temperature sensor 52, a temperature detection value of the
receiving part 13 is obtained again (Step S5). It is determined
whether or not the temperature detection value of the receiving
part 13 is less than a temperature lower limit threshold (Step
S6).
[0054] When the temperature detection value of the receiving part
13 is equal to or greater than the temperature lower limit
threshold (NO), supply of the water W to the receiving part 13, is
continued (Step S4). When the temperature detection value of the
receiving part 13 is less than the temperature lower limit
threshold (YES), the valve 52 is closed to stop supply of the water
W to the receiving part 13 (Step S7). Note that the supply rate of
the water W to the receiving part 13 may be adjusted corresponding
to the temperature detection value of the receiving part 13.
[0055] The work described above may be performed repeatedly in a
situation in which the die 12 of the main roll 1 is inductively
heated by the induction heating mechanism 6, and thereby,
temperature distribution in the shaft 11 and the die 12 of the main
roll 1 may be controlled appropriately. It is suitable that this
cooling method be performed in a state in which the main roll 1
rotates. However, it is possible to perform it in a state in which
the rotation of the main roll 1 is stopped. Note that at least one
of the works in the cooling method may be performed manually by an
operator.
[0056] In the cooling method, the temperature upper limit threshold
and the temperature lower threshold may be defined as described
below. It is preferable that the temperature upper limit threshold
be approximately 150 degrees C., and that the temperature lower
limit threshold be approximately 40 degrees C. That is, it is
preferable that the temperature detection value of the receiving
part 13 be maintained between approximately 40 degrees C. or more,
but approximately 150 degrees C. or less.
[0057] However, the present invention is not limited thereto. The
temperature upper limit threshold may be more than the temperature
lower limit threshold, and the temperature upper limit threshold
may be less than the temperature of the receiving part determined
corresponding to the heat resistance temperature of the bearing
part on the basis of the heat conduction conditions from the
receiving part of the die to the bearing part of the shaft.
[0058] Regarding Method of Manufacturing Ring Rolled Body
[0059] A method for manufacturing a ring rolled body, according to
the present Embodiment will be described with reference to FIGS. 1
and 5. In the manufacturing method, a process of controlling the
temperature of the main roll 1 so as to cool the shaft 11 and the
peripheral portion thereof of the main roll 1 while heating the die
12 of the main roll 1 (hereinafter referred to as a "temperature
control process"), and a process of performing ring rolling on the
pre-heated ring material M (hereinafter referred to as a "rolling
process") are performed. Regarding the rolling process, it is
preferable that the temperature of the pre-heated ring material M
be approximately 850 degrees C. or more, but approximately 1150
degrees C. or less. However, the temperature of the ring material
is not limited thereto. It is adjustable according to the type of
the metal material used for the ring material so as to produce a
high quality ring rolled body.
[0060] First, the temperature control process is performed.
Specifically, the main roll 1 is rotated (Process P1). A work to
inductively heat the main roll 1 by the induction heating mechanism
6 (hereinafter referred to as an "induction heating work") and a
work to cool the main roll 1 by the cooling method (hereinafter
referred to as a "cooling work") are started (Process P2).
Thereafter, when the temperature distribution in the shaft 11 and
the die 12 of the main roll 1 has been properly controlled (Process
P3), the induction heating work and the cooling work terminate
(Process P4). Furthermore, rotation of the main roll 1 is stopped
(Process P5). Note that during the energization of the induction
heating mechanism 6, when a problem, such as electrical ground
fault or the like arises, it is preferable to stop supply of the
water W from the liquid supply mechanism 5 to the receiving part
13.
[0061] Next, the rolling process is performed. Specifically, the
pre-heated ring material M is mounted on the rolling mill (Process
P6). The main roll 1 and the mandrel 2 are rotated, and the pair of
axial rolls 3, 4 is rotated. Along with the rotation, the ring
material M is rotated toward the one side (indicated by arrow F) in
the ring circumferential direction about the central axis C thereof
(Process P7). The induction heating work is started again (Process
P8). A work to reduce the ring material M in the ring radial
direction by the main roll 1 and the mandrel 2, and a work to
reduce the ring material M in the ring axial direction by the pair
of axial rolls 3, 4, are repeated in this order (hereinafter
referred to as a "reduction work") (Process P9). At this time, the
main roll 1 and mandrel 2 are moved relative to the ring radial
direction with reference to the center in the radial direction of
the ring material M, whereby the ring material M can be deformed so
as to increase its diameter. When the ring material M is deformed
into a desired shape (Process P10), the reduction work terminates.
At the same time, the induction heating work on the main roll 1
terminates (Process P11). Thereafter, rotation of the ring material
M is stopped (Process P12). Note that the induction heating work
need not be stopped temporarily and may continue during transition
from the temperature control process to the rolling process. The
cooling work may be performed during the reduction work. After the
termination of the rolling process, if the shaft 11 and the
peripheral portion thereof of the main roll 1 have residual heat in
particular, it is preferable to further perform the cooling
work.
[0062] Regarding Details of Induction Heating Work
[0063] Here, details of the induction heating work will be
described. As described above, the induction heating work is
performed in a substantially continuous manner during the time from
the start thereof until the start of the reduction work, and it is
also performed during reduction of the ring material M. Before the
reduction work, the induction heating work is performed so as to
cause the temperature of the processed part of the outer peripheral
surface 12a of the die 12 in the main roll 1 to be a pre-determined
temperature (hereinafter referred to as a "pre-reduction heating
temperature) for a pre-determined time (hereinafter referred to as
a "pre-reduction heating time"). During the reduction work, the
induction heating work is performed so as to cause the temperature
of the processed part of the outer peripheral surface 12a of the
die 12 in the main roll 1 to be a pre-determined temperature
(hereinafter referred to as an "in-reduction heating
temperature").
[0064] The pre-reduction heating time, the pre-reduction heating
temperature, and the in-reduction heating temperature may be as
described below. Considering: heating the die 12 of the main roll 1
sufficiently before the reduction work so as to efficiently enhance
the quality of the ring rolled body to be produced; and performing
induction heating during the reduction work, the pre-reduction
heating time may be approximately 3 minutes or more, and the
pre-reduction heating temperature may be approximately 100 degrees
C. or more. The pre-reduction heating temperature is preferably
approximately 150 degrees C. or more, and is more preferably,
approximately 300 degrees C. or more.
[0065] On the other hand, considering preventing softening of the
main roll 1 and preventing reduction in the manufacturing
efficiency of the ring rolled body, the pre-reduction heating time
may be approximately one hour or less, and the pre-reduction
heating temperature may be less than the softening temperature of
the material of the main roll 1. Specifically, in the case in which
the material of the outer peripheral surface 12a of the die 12 in
the main roll 1 is steel for hot-working die defined by JIS G4404
or improved steel thereof, the pre-reduction heating temperature is
preferably less than the tempering temperature. That is, the
softening temperature may be the tempering temperature. In the case
in which the material of the main roll 1 requires strength and heat
resistance, a Ni-based superalloy may be used. In that case, the
pre-reduction heating temperature is preferably less than the
solution treatment temperature. That is, the softening temperature
may be the solution treatment temperature.
[0066] Furthermore, the in-reduction heating temperature preferably
ranges from approximately 300 degrees C. to the temperature of the
pre-heated ring material M. The upper limit value is preferably set
according to the material and/or the like of the main roll 1. In
particular, the upper limit value is preferably set to a
temperature which enables the main roll 1 to be prevented from
softening. That is, the in-reduction heating temperature is
preferably less than the softening temperature of the die 12 in the
main roll 1, in the same manner as the pre-reduction heating
temperature.
[0067] Furthermore, the temperature of the induction heating by the
induction heating mechanism 6 is preferably adjusted such that the
temperature distribution in the radial direction of the ring
material M is efficiently controllable within an appropriate
temperature range while suppressing heat extraction of the ring
material M, within the aforementioned range. As an example, the
temperature of the induction heating by the induction heating
mechanism 6 is preferably adjusted to equalize the temperature
distribution in the radial direction of the ring material M.
[0068] However, the present invention is not limited thereto. The
method of manufacturing a ring rolled body may be made as described
below. The induction heating work may terminate before or after the
termination of the reduction work. The timing of restarting the
induction heating work after temporal interruption before the start
of the reduction work of the ring material may be immediately
before the start of, at the start of, or after the start of the
reduction work of the ring material. In particular, the
interruption time of the induction heating work is preferably set
within a range in which the temperature of the main roll which can
efficiently enhance the quality, such as dimension accuracy of the
ring rolled body to be produced, is maintained. Furthermore, the
reduction work may be performed in a state in which the induction
heating work is stopped. In that case, the pre-reduction heating
time may be approximately 15 minutes or more, but approximately 2
hours or less, and is preferably approximately 30 minutes or more,
but approximately 1 hour or less.
[0069] Actions and Effects
[0070] As described above, in the method of cooling the main roll 1
according to the present Embodiment, the receiving part 13 which is
recessed from the upper end surface 12c of the die 12 of the main
roll 1 and surrounds the shaft 11 of the main roll 1, receives the
water W, and the main roll 1 is cooled by the water W in the
receiving part 13. Therefore, the shaft 11 can be cooled
efficiently. On the other hand, the receiving part 13 is apart from
the processed part (including the recessed part 12b) of the outer
peripheral surface 12a of the die 12 which contacts the ring
material M. Therefore, it is possible to efficiently prevent a
temperature drop in the processed part of the die 12 and the ring
material M which contacts it. Accordingly, the shaft 11 and the
peripheral portion thereof of the main roll 1 can be cooled
efficiently. Since the receiving part 13 widely opens toward the
outside of the main roll 1 at the upper end surface 12c of the die
12, it is possible to easily clean the inside thereof from the
opening of the receiving part 13. Therefore, maintenance of the
main roll 1 can be performed easily. Since the receiving part 13 is
formed in the die 12, it is possible to prevent the strength of the
shaft 11 from being decreased by the cooling structure of the main
roll 1. Therefore, the strength of the rotation support structure
of the main roll 1 can be secured sufficiently.
[0071] In the method of cooling the main roll 1 of the present
Embodiment, the water W injected in the receiving part 13 flows
through the liquid passages 14 which extend from the receiving part
13 toward the other side in the rotation axis direction in the die
12 and are spaced apart from each other in the circumferential
direction of the main roll. Therefore, the water W is stored in the
receiving part 13, and thereafter, the water W in the receiving
part 13 is sent to the liquid passages 14. As a result, the water W
is retained in the main roll 1 so as to enable the main roll 1, in
particular, the shaft 11, to be cooled efficiently. Furthermore,
since the liquid passages 14 provided to the main roll 1 in
addition to the receiving part 13, are spaced apart from each other
in the circumferential direction of the main roll 1, it is possible
to prevent the strength of the main roll 1 from being decreased by
the added liquid passages 14. That is, the strength of the main
roll 1 can be secured sufficiently.
[0072] In the method of cooling the main roll 1 of the present
Embodiment, the water W flowing through the liquid passages 14, is
discharged from the outlets 14b of the liquid passages 14 which
open at the lower end surface 12d of the die 12 of the main roll 1,
to the outside of the main roll 1. Therefore, since the water W in
the main roll 1 is replaceable, the main roll 1 can be cooled
effectively.
[0073] In the method of manufacturing the ring rolled body of the
present Embodiment, even if the die 12 of the roll 1 is heated, the
shaft 11 of the main roll 1 can be efficiently cooled by the
cooling method. Compared with the case of directly heating the ring
material M which is deformed during ring rolling, heating the main
roll 1 which maintains a certain shape, causes the temperature
control in the hot ring rolling to be easier. That is, it is
possible to accurately control the temperature of the processed
part of the die 12 which applies hot ring rolling to the ring
material M, while cooling the shaft 11 which is necessary to be
prevented from being exposed to high temperature. Therefore, a
high-quality ring rolled body can be produced by the hot ring
rolling using the main roll 1 which enables accurate temperature
control as described above.
Second Embodiment
[0074] A method of cooling a main roll, a method of manufacturing a
ring rolled body, and a rolling mill, according to a Second
Embodiment of the present invention, will be described. The method
of cooling the main roll and the method of manufacturing the ring
rolled body, according to the present Embodiment, are the same as
those of the First Embodiment. The rolling mill according to the
present Embodiment is the same as that of the First Embodiment
except for the liquid passages in the cooling structure of the main
roll.
[0075] Regarding Liquid Passage in Cooling Structure of Main
Roll
[0076] With reference to FIG. 6, a liquid passage 16 in the cooling
structure of the main roll 1 will be described. A die 12 of the
main roll 1 of the present Embodiment includes a plurality of
liquid passages 16 which are formed in a blind hole shape, instead
of the liquid passages 14 which penetrate through as in the First
Embodiment. Each of the liquid passages 16 has an inlet 16a which
opens at the receiving part 13, and a bottom 16b which is
positioned at the lower end thereof. The other configurations of
the liquid passage 16 are the same as those of the liquid passage
14 of the First Embodiment.
[0077] Actions and Effects
[0078] As described above, in the method of cooling the main roll 1
of the present Embodiment, the actions and effects as described
below can be achieved, instead of the actions and effects provided
by the liquid passages 14 which penetrate in the method of cooling
the main roll 1 of the First Embodiment. That is, since the water W
flowing into the liquid passage 16 which is formed in a blind hole
shape, is stored on and above the bottom 16b of the liquid passage
16, the water W evaporates in the main roll 1, and furthermore, by
the heat of vaporization due to evaporation, the main roll 1, in
particular the shaft 11 and the peripheral portion thereof of the
main roll 1 can be cooled effectively. Note that the other actions
and effects based on the method of cooling the main roll 1
according to the present Embodiment and the actions and effects
based on the method of manufacturing the ring rolled body are the
same as those of the First Embodiment.
Third Embodiment
[0079] A method of cooling a main roll, a method of manufacturing a
ring rolled body, and a rolling mill, according to a Third
Embodiment of the present invention, will be described. The method
of cooling the main roll and the method of manufacturing the ring
rolled body, according to the present Embodiment, are the same as
those of the First Embodiment. The rolling mill according to the
present Embodiment is the same as that of the First Embodiment
except for the receiving part in the cooling structure of the main
roll.
[0080] Regarding receiving part in cooling structure of main roll
With reference to FIG. 7, a receiving part 17 in the cooling
structure of the main roll 1 will be described. A die 12 of the
main roll 1 in the present Embodiment has a receiving part 17 which
is recessed downward from the upper end surface 12c thereof. The
receiving part 17 opens at the upper end surface 12c of the die 12,
and extends in the circumferential direction of the main roll 1 so
as to surround the shaft 11. The receiving part 17 receives the
water W supplied from the liquid supply mechanism 5.
[0081] The receiving part 17 includes an opening edge 17a which is
formed on the upper end surface 12c of the die 12, a bottom surface
17b facing the opening edge 17a, and an inner peripheral surface
17c located between the opening edge 17a and the outer peripheral
edge of the bottom surface 17b. The bottom surface 17b is formed in
a recessed shape in a tapered manner toward the inlet 14a of the
liquid passage 14. Therefore, the water W in the receiving part 17
can be efficiently guided to the liquid passage 14 by the bottom
surface 17b. Furthermore, an upper area of the inner peripheral
surface 17c has a protrusion 17d which protrudes to the rotation
axis 1a side of the main roll 1 relative to the lower area.
Therefore, by the protrusion 17d, it is possible to prevent the
water W in the receiving part 17 from leaking outside from the
opening of the receiving part 17 during rotation of the main roll
1.
[0082] It is also preferable that the bottom surface 17b of the
receiving part 17 be located above the processed part of the outer
peripheral surface 12a of the die 12, in the same manner as the
First Embodiment. As an example, in the same manner as the First
Embodiment, since centrifugal force is applied to the liquid, such
as the water W in the receiving part 17 during rotation of the main
roll 1, the bottom surface 17b may be formed so as to realize a
depth of the receiving part 17 which can hold the liquid in the
receiving part 17. Furthermore, in the same manner as the First
Embodiment, the maximum distance from the rotation axis 1a of the
main roll 1 to the inner peripheral surface 17c of the receiving
part 17 may be equal to or less than 3/4 of the minimum distance
from the rotation axis 1a of the main roll 1 to the outer
peripheral surface 12a of the die 12, and may be preferably, equal
to or less than a half of the minimum distance.
Fourth Embodiment
[0083] Regarding a method of cooling a main roll, a method of
manufacturing a ring rolled body, and a rolling mill according to a
Fourth Embodiment of the present invention, the method of cooling
the main roll and the method of manufacturing the ring rolled body
are the same as those of the Second Embodiment. Furthermore, the
rolling mill according to the present Embodiment is the same as
that of the Second Embodiment, except that the die of the main roll
has the receiving part in the same manner as that of the Third
Embodiment.
[0084] Although Embodiments of the present invention have been
described, the present invention is not limited to the Embodiments
described above. The present invention can be modified and changed
based on the technical concept.
[0085] For example, as a First Modification of the present
invention, the die of the main roll in the First to Fourth
Embodiments may have a plurality of liquid passages including: a
liquid passage/liquid passages penetrating as in the First and
Third Embodiments; and a liquid passage/liquid passages formed in a
blind hole shape as in the Second and Fourth Embodiments.
[0086] As a Second Modification of the present invention, the die
of the main roll in the First to Fourth Embodiments may be
configured so as not to have a liquid passage.
REFERENCE SIGNS LIST
[0087] 1 Main roll, 1a Rotation axis, 11 Shaft, 12 Die, 12c Upper
end surface, 12d Lower end surface, 13 Receiving part, 13b Bottom
surface, 14 Liquid passage, 14b Outlet, 16 Liquid passage, 16b
Bottom, 17 Receiving part, 17b Bottom surface, 2 Mandrel, M Ring
material, m1 Outer peripheral surface, m2 Inner peripheral surface,
W Water, S1 to S6 Step, P1 to P12 Process, R1, R2, F Arrow
* * * * *