U.S. patent application number 16/495033 was filed with the patent office on 2020-08-27 for production method and production facility for steel sheet pile with flanges.
This patent application is currently assigned to NIPPON STEEL CORPORATION. The applicant listed for this patent is NIPPON STEEL CORPORATION. Invention is credited to Shinya HAYASHI, Masanori KAWAI, Kazunori SEKI, Hiroshi YAMASHITA.
Application Number | 20200269294 16/495033 |
Document ID | / |
Family ID | 1000004855166 |
Filed Date | 2020-08-27 |
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United States Patent
Application |
20200269294 |
Kind Code |
A1 |
HAYASHI; Shinya ; et
al. |
August 27, 2020 |
PRODUCTION METHOD AND PRODUCTION FACILITY FOR STEEL SHEET PILE WITH
FLANGES
Abstract
To suppress the occurrence of a defective shape such as a flange
wave or the like by reverse rolling so as to improve the product
dimension accuracy and stability of rolling. A production method
for forming a steel sheet pile with flanges from a material to be
rolled by caliber roll rolling, includes a step of performing
reverse rolling on the material to be rolled by a same caliber,
wherein: the step of performing reverse rolling includes a step of
forming first flange parts across a neutral line and second and
third flange parts arranged on both sides of the first flange
parts; the caliber includes first flange facing portions for
forming the first flange parts, second flange facing portions for
forming the second flange parts, and third flange facing portions
for forming the third flange parts; and an inclination angle of the
first flange facing portion with respect to a horizontal plane is
larger than inclination angles of the second and third flange
facing portions.
Inventors: |
HAYASHI; Shinya; (Tokyo,
JP) ; YAMASHITA; Hiroshi; (Tokyo, JP) ; SEKI;
Kazunori; (Tokyo, JP) ; KAWAI; Masanori;
(Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NIPPON STEEL CORPORATION |
Tokyo |
|
JP |
|
|
Assignee: |
NIPPON STEEL CORPORATION
Tokyo
JP
|
Family ID: |
1000004855166 |
Appl. No.: |
16/495033 |
Filed: |
April 3, 2018 |
PCT Filed: |
April 3, 2018 |
PCT NO: |
PCT/JP2018/014214 |
371 Date: |
September 17, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B21B 1/082 20130101;
B21B 1/095 20130101; E02D 5/04 20130101; B21B 1/14 20130101; B21B
2001/081 20130101 |
International
Class: |
B21B 1/082 20060101
B21B001/082; B21B 1/095 20060101 B21B001/095; B21B 1/14 20060101
B21B001/14 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 3, 2017 |
JP |
2017-073578 |
Claims
1. A production method for forming a steel sheet pile with flanges
from a material to be rolled by caliber roll rolling, the
production method comprising a step of performing reverse rolling
on the material to be rolled by a same caliber, wherein: the step
of performing reverse rolling comprises a step of forming first
flange parts across a neutral line and second and third flange
parts arranged on both sides of the first flange parts; the caliber
comprises first flange facing portions for forming the first flange
parts, second flange facing portions for forming the second flange
parts, and third flange facing portions for forming the third
flange parts; and an inclination angle of the first flange facing
portion with respect to a horizontal plane is larger than
inclination angles of the second and third flange facing
portions.
2. The production method for a steel sheet pile with flanges
according to claim 1, wherein: the step of performing reverse
rolling comprises a step of forming a web corresponding part and
arm corresponding parts; the caliber comprises a web facing portion
for forming the web corresponding part and arm facing portions for
forming the arm corresponding parts; the caliber comprises web-side
flange facing portion groups each including at least one of the
second flange facing portions and arm-side flange facing portion
groups each including at least one of the third flange facing
portions; and with respect to a straight line linking a boundary
part between the web-side flange facing portion group and the web
facing portion and a boundary part between the arm-side flange
facing portion group and the arm facing portion, the second flange
facing portion is in a protruding shape in a flange outside
direction, and the third flange facing portion is in a protruding
shape in a flange inside direction.
3. The production method for a steel sheet pile with flanges
according to claim 1, wherein rolling in which a flange elongation
.lamda.f1 at the first flange part is smaller than flange
elongations .lamda.f2, .lamda.f3 at the second flange part and the
third flange part is performed in the caliber.
4. The production method for a steel sheet pile with flanges
according to claim 1, wherein the step of forming the first flange
parts, the second flange parts, and the third flange parts is an
intermediate rolling step.
5. The production method for a steel sheet pile with flanges
according to claim 4, wherein the caliber has a caliber shape
opened at both end parts in a width direction.
6. The production method for a steel sheet pile with flanges
according to claim 1, wherein the flange corresponding parts in a
bent shape formed in the material to be rolled by the step of
forming the first flange parts, the second flange parts, and the
third flange parts are rolled and shaped into a desired flat shape
by rolling in a caliber at a stage subsequent to the step of
forming the first flange parts, the second flange parts, and the
third flange parts.
7. The production method for a steel sheet pile with flanges
according to claim 1, wherein rolling is performed in the caliber
so that the flange elongation .lamda.f1 at the first flange part
becomes a web elongation .lamda.w or less.
8. The production method for a steel sheet pile with flanges
according to claim 1, wherein the steel sheet pile is a hat-shaped
steel sheet pile.
9. A production facility for forming a steel sheet pile with
flanges from a material to be rolled by caliber roll rolling, the
production facility comprising a rolling mill which performs
reverse rolling on the material to be rolled by a same caliber,
wherein: the rolling mill which performs reverse rolling comprises
a caliber which forms first flange parts across a neutral line and
second and third flange parts arranged on both sides of the first
flange parts; the caliber comprises first flange facing portions
for forming the first flange parts, second flange facing portions
for forming the second flange parts, and third flange facing
portions for forming the third flange parts; and an inclination
angle of the first flange facing portion with respect to a
horizontal plane is larger than inclination angles of the second
and third flange facing portions.
10. The production facility for a steel sheet pile with flanges
according to claim 9, wherein: the rolling mill which performs
reverse rolling comprises a caliber which forms a web corresponding
part and arm corresponding parts; the caliber comprises a web
facing portion for forming the web corresponding part and arm
facing portions for forming the arm corresponding parts; the
caliber comprises web-side flange facing portion groups each
including at least one of the second flange facing portions and
arm-side flange facing portion groups each including at least one
of the third flange facing portions; and with respect to a straight
line linking a boundary part between the web-side flange facing
portion group and the web facing portion and a boundary part
between the arm-side flange facing portion group and the arm facing
portion, the second flange facing portion is in a protruding shape
in a flange outside direction, and the third flange facing portion
is in a protruding shape in a flange inside direction.
11. The production facility for a steel sheet pile with flanges
according to claim 9, wherein a flange elongation .lamda.f1 at the
first flange part is smaller than flange elongations .lamda.f2,
.lamda.f3 at the second flange part and the third flange part in
the caliber.
12. The production facility for a steel sheet pile with flanges
according to claim 9, wherein the caliber is a caliber provided in
an intermediate rolling mill.
13. The production facility for a steel sheet pile with flanges
according to claim 12, wherein the caliber has a caliber shape
opened at both end parts in a width direction.
14. The production facility for a steel sheet pile with flanges
according to claim 9, further comprising a subsequent-stage caliber
which rolls and shapes the flange corresponding parts in a bent
shape formed in the material to be rolled by rolling in the caliber
which forms the first flange parts, the second flange parts, and
the third flange parts, into a desired flat shape.
15. The production facility for a steel sheet pile with flanges
according to claim 9, wherein the flange elongation .lamda.f1 at
the first flange part is a web elongation .lamda.w or less in the
caliber.
16. The production facility for a steel sheet pile with flanges
according to claim 9, wherein the steel sheet pile is a hat-shaped
steel sheet pile.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based upon and claims the benefit of
priority of the prior Japanese Patent Application No. 2017-073578,
filed in Japan on Apr. 3, 2017, the entire contents of which are
incorporated herein by reference.
TECHNICAL FIELD
[0002] The present invention relates to a production method and a
production facility for a steel sheet pile with flanges such as a
hat-shaped steel sheet pile, a U-shaped steel sheet pile or the
like.
BACKGROUND ART
[0003] Conventionally, the production of a steel sheet pile having
joints at both ends of a hat shape or the like is performed by a
caliber rolling method. Known as a general process of the caliber
rolling method is, first, heating a rectangular material to a
predetermined temperature in a heating furnace and sequentially
rolling the rectangular material by a rough rolling mill, an
intermediate rolling mill, and a finish rolling mill including
calibers. As the caliber rolling method, a technique of arranging a
plurality of calibers at rolls in rough rolling, intermediate
rolling, and finish rolling and performing rolling in one to two
passes in each of the calibers to produce a hat-shaped steel sheet
pile is disclosed, for example, in Patent Document 1.
[0004] Besides, a technique of constituting a caliber to balance
web and flange elongations in the production of a U-shaped steel
sheet pile and performing rolling by reciprocating a material to be
rolled a plurality of times in the same caliber is disclosed, for
example, in Patent Document 2. Besides, a technique for the purpose
of reducing the placing resistance in constructing a steel sheet
pile is disclosed and a configuration in which a gradually inclined
part is provided at a flange part is proposed, for example, in
Patent Document 3.
[0005] Further, a production technique for a Z-shaped steel sheet
pile including a step of shaping a pre-form having two flange/web
transition sections parallel to a rolling plane and a middle
section inclined with respect to the rolling plane near a neutral
line is disclosed, for example, in Patent Document 4.
[0006] As described above, the caliber rolling method and the
technique of performing rolling by reciprocating the material to be
rolled a plurality of times in the same caliber (so-called
one-caliber multiple-pass rolling) are conventionally invented as
the production method for a steel sheet pile.
PRIOR ART DOCUMENT
[0007] [Patent Document] [0008] Patent Document 1: Japanese
Laid-open Patent Publication No. 2006-88176 [0009] Patent Document
2: Japanese Laid-open Patent Publication No. S60-44101 [0010]
Patent Document 3: Japanese Laid-open Patent Publication No.
[0011] 2004-76580 [0012] Patent Document 4: Japanese Laid-open
Patent Publication No. H8-224634
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0013] However, in the above conventional caliber rolling method
exemplified in the above Patent Document 1, the rolling in one to
two passes in one caliber is performed at the rough rolling, the
intermediate rolling step to the finish rolling step with the
flange set to a linear state at substantially the same angle as
that of the product but, in particular, in the case where the
flange width is large and the sheet thickness is small, when the
reverse rolling is performed, the elongation at each part in the
cross section of the material to be rolled cannot be balanced,
causing a flange wave in some cases. Note that the "caliber" in the
description is a gap formed between upper and lower caliber rolls
and indicates a portion through which the material to be rolled is
passed and rolled. Hereinafter, as long as the grooves on the rolls
forming the caliber are the same if the distance between the upper
and lower caliber rolls varies, the caliber will be explained while
being called "the same caliber". Further, the "reverse rolling" in
the description means a step of repeatedly performing rolling by
reciprocating the material to be rolled in a plurality of passe
while gradually narrowing the roll gap in the same caliber
constituted of the upper and lower caliber rolls.
[0014] Besides, in the technique disclosed in the above Patent
Document 2, in the case of performing rolling that takes large
elongation, in particular, for a large-sized steel sheet pile
having a large flange width and a small flange thickness as
compared with the conventional one, like a hat-shaped steel sheet
pile, a defective shape such as a flange wave or the like occurs
even if balancing the elongations described in the above Patent
Document 2, so that the stable rolling and shaping is difficult and
a product defective shape possibly occurs. Further, the balancing
condition appropriate for suppressing the occurrence of the
defective shape such as a flange wave or the like cannot be
realized in some cases in the constraint of the rolling mill. In
recent years, in fact, a steel sheet pile in a large cross section
having a large height and a small sheet thickness is demanded from
the viewpoint of economy and construction property, and a further
improvement of technique is required in the production of the
large-sized steel sheet pile.
[0015] Besides, regarding the technique disclosed in the above
Patent Document 3, it is stated that a gradually inclined part is
provided at a part (at one or more places of a corner part formed
by an end flange part and a web part and a middle part of a web
part) of a web part (defined as a flange part in the present
invention) to reduce the placing resistance and improve the
construction property, but the defective shape such as a flange
wave or the like in the production process is not mentioned at all.
A further improvement of technique regarding realization of the
suppression of the defective shape and the realization of stable
rolling and shaping and so on in the production of the large-sized
steel sheet pile is demanded.
[0016] Besides, the technique disclosed in the above Patent
Document 4 is considered to be a technique of performing
one-caliber one-pass rolling, and there is no description of
performing so-called reverse rolling of performing a plurality of
passes while gradually narrowing the gap between the upper and
lower rolls in the same caliber. This is considered to be because
if the reverse rolling is performed in the same caliber in the
technique described in Patent Document 4, the elongation becomes
nonuniform at each part in the cross section, metal flow occurs to
change the filling stage at the joint part and the elongation of a
flange/web transition section becomes geometrically larger than the
elongation at a middle section, resulting in that twist becomes
more likely to occur. In the case of performing one-caliber
one-pass rolling, the caliber shape can be made into an optimum
shape during one-pass rolling, so that the problem such as a
defective shape of the material to be rolled caused by the caliber
shape cannot arise. In short, in the above Patent Document 4, the
occurrence of the flange wave possibly occurring during the reverse
rolling is not mentioned at all and the suppress of the flange wave
is not mentioned at all as a matter of course.
[0017] Hence, in consideration of the above circumstances, an
object of the present invention is to provide a production
technique for a steel sheet pile with flanges, capable of
suppressing the occurrence of a defective shape such as a flange
wave or the like by reverse rolling so as to improve the product
dimension accuracy and stability of rolling.
Means for Solving the Problems
[0018] To achieve the above object, according to the present
invention, there is provided a production method for forming a
steel sheet pile with flanges from a material to be rolled by
caliber roll rolling, the production method including a step of
performing reverse rolling on the material to be rolled by a same
caliber, wherein: the step of performing reverse rolling includes a
step of forming first flange parts across a neutral line and second
and third flange parts arranged on both sides of the first flange
parts; the caliber includes first flange facing portions for
forming the first flange parts, second flange facing portions for
forming the second flange parts, and third flange facing portions
for forming the third flange parts; and an inclination angle of the
first flange facing portion with respect to a horizontal plane is
larger than inclination angles of the second and third flange
facing portions.
[0019] It is adoptable that the step of performing reverse rolling
includes a step of forming a web corresponding part and arm
corresponding parts; the caliber includes a web facing portion for
forming the web corresponding part and arm facing portions for
forming the arm corresponding parts; the caliber includes web-side
flange facing portion groups each including at least one of the
second flange facing portions and arm-side flange facing portion
groups each including at least one of the third flange facing
portions; and with respect to a straight line linking a boundary
part between the web-side flange facing portion group and the web
facing portion and a boundary part between the arm-side flange
facing portion group and the arm facing portion, the second flange
facing portion is in a protruding shape in a flange outside
direction, and the third flange facing portion is in a protruding
shape in a flange inside direction.
[0020] It is adoptable that rolling in which a flange elongation
.kappa.f1 at the first flange part is smaller than flange
elongations .lamda.f2, .lamda.f3 at the second flange part and the
third flange part is performed in the caliber.
[0021] It is adoptable that the step of forming the first flange
parts, the second flange parts, and the third flange parts is an
intermediate rolling step.
[0022] It is adoptable that the caliber has a caliber shape opened
at both end parts in a width direction.
[0023] It is adoptable that the flange corresponding parts in a
bent shape formed in the material to be rolled by the step of
forming the first flange parts, the second flange parts, and the
third flange parts are rolled and shaped into a desired flat shape
by rolling in a caliber at a stage subsequent to the step of
forming the first flange parts, the second flange parts, and the
third flange parts.
[0024] It is adoptable that rolling is performed in the caliber so
that the flange elongation .kappa.f1 at the first flange part
becomes a web elongation .lamda.w or less.
[0025] It is adoptable that the steel sheet pile is a hat-shaped
steel sheet pile.
[0026] According to the present invention from another viewpoint,
there is provided a production facility for forming a steel sheet
pile with flanges from a material to be rolled by caliber roll
rolling, the production facility including a rolling mill which
performs reverse rolling on the material to be rolled by a same
caliber, wherein: the rolling mill which performs reverse rolling
includes a caliber which forms first flange parts across a neutral
line and second and third flange parts arranged on both sides of
the first flange parts; the caliber includes first flange facing
portions for forming the first flange parts, second flange facing
portions for forming the second flange parts, and third flange
facing portions for forming the third flange parts; and an
inclination angle of the first flange facing portion with respect
to a horizontal plane is larger than inclination angles of the
second and third flange facing portions.
[0027] It is adoptable that the rolling mill which performs reverse
rolling includes a caliber which forms a web corresponding part and
arm corresponding parts; the caliber includes a web facing portion
for forming the web corresponding part and arm facing portions for
forming the arm corresponding parts; the caliber includes web-side
flange facing portion groups each including at least one of the
second flange facing portions and arm-side flange facing portion
groups each including at least one of the third flange facing
portions; and with respect to a straight line linking a boundary
part between the web-side flange facing portion group and the web
facing portion and a boundary part between the arm-side flange
facing portion group and the arm facing portion, the second flange
facing portion is in a protruding shape in a flange outside
direction, and the third flange facing portion is in a protruding
shape in a flange inside direction.
[0028] It is adoptable that a flange elongation .lamda.f1 at the
first flange part is smaller than flange elongations .lamda.f2,
.lamda.f3 at the second flange part and the third flange part in
the caliber.
[0029] It is adoptable that the caliber is a caliber provided in an
intermediate rolling mill.
[0030] It is adoptable that the caliber has a caliber shape opened
at both end parts in a width direction.
[0031] It is adoptable to further include a subsequent-stage
caliber which rolls and shapes the flange corresponding parts in a
bent shape formed in the material to be rolled by rolling in the
caliber which forms the first flange parts, the second flange
parts, and the third flange parts, into a desired flat shape.
[0032] It is adoptable that the flange elongation .lamda.f1 at the
first flange part is a web elongation .lamda.w or less in the
caliber.
[0033] It is adoptable that the steel sheet pile is a hat-shaped
steel sheet pile.
Effect of the Invention
[0034] According to the present invention, it becomes possible to
suppress the occurrence of a defective shape such as a flange wave
or the like by reverse rolling so as to improve the product
dimension accuracy and stability of rolling.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] FIG. 1 is a schematic explanatory view of a rolling
line.
[0036] FIG. 2 is a schematic cross-sectional view illustrating the
caliber shape of a first caliber.
[0037] FIG. 3 is a schematic cross-sectional view illustrating the
caliber shape of a second caliber.
[0038] FIG. 4 is a schematic cross-sectional view illustrating the
caliber shape of a third caliber.
[0039] FIG. 5 is a schematic cross-sectional view illustrating the
caliber shape of a fourth caliber.
[0040] FIG. 6 is a schematic cross-sectional view illustrating the
caliber shape of a fifth caliber.
[0041] FIG. 7 is a schematic explanatory view of a caliber in a
configuration obtained by modifying the third caliber, and (a)
illustrating a schematic entire view and (b) illustrating an
enlarged view near a place facing a flange corresponding part.
[0042] FIG. 8 is a schematic explanatory view according to a
modification example of the present invention.
[0043] FIG. 9 is an explanatory view of an example.
[0044] FIG. 10 is a schematic explanatory view according to a
modification example of the present invention.
[0045] FIG. 11 is a schematic explanatory view according to a
modification example of the present invention.
[0046] FIG. 12 is a schematic explanatory view according to a
modification example of the present invention.
EMBODIMENTS FOR CARRYING OUT THE INVENTION
[0047] Hereinafter, an embodiment of the present invention will be
explained referring to the drawings. Note that, in the description
and the drawings, the same codes are given to components having
substantially the same functional configurations to omit duplicated
explanation. Note that the explanation will be made assuming that a
material to be rolled in a substantially hat-shaped steel sheet
pile shape is rolled in a posture that the web is located below the
flange (so-called U-posture) in the embodiment, and the scope of
application of the present invention extends, as a matter of
course, to rolling in other postures (for example, an inverted
U-posture). Further, the scope of application of the present
invention ranges over steel sheet pile products having various
flanges in a hat shape, a U-shape and so on, and a steel sheet pile
product produced in the embodiment will be explained as a
hat-shaped steel sheet pile product.
[0048] Besides, a material to be rolled A described below indicates
a steel material to be rolled in the case of producing the
hat-shaped steel sheet pile product, steel materials to be passed
on a rolling line L are generically called the material to be
rolled A, and the material to be rolled A in states that it has
been subjected to reduction in rolling mills are described
separately using different names (A1 to A5 described below) as
needed. The material to be rolled A is in a substantial hat shape,
and is composed of a substantially horizontal web corresponding
part 3, flange corresponding parts 5, 6 connected to both ends of
the web corresponding part 3 at a predetermined angle, arm
corresponding parts 8, 9 connected to ends of the flange
corresponding parts 5, 6 different from the sides thereof connected
with the web corresponding part 3, and joint corresponding parts
10, 11 connected to tips of the arm corresponding parts 8, 9. Note
that end portions of the joint corresponding parts 10, 11 are
called claw parts 14, 15, respectively. Hereinafter, parts
constituting the material to be rolled A will be illustrated and
explained with the aforementioned respective codes.
[0049] Note that, regarding the material to be rolled A, the
rolling direction is called a "longitudinal direction" of the
material to be rolled, a direction perpendicular to the
longitudinal direction and parallel with a rolling roll axis is
called a "width direction" of the material to be rolled, and a
direction perpendicular to both the longitudinal direction and the
width direction is called a "height direction" of the material to
be rolled, for explanation in this description. Further, a
"thickness reduction" of the material to be rolled indicates a
sheet thickness reduction in the sheet thickness direction of the
material to be rolled.
[0050] First of all, the outline of the rolling line L being a
basic configuration as a producing apparatus 1 for producing the
hat-shaped steel sheet pile will be explained. FIG. 1 is an
explanatory view of the rolling line L for producing the hat-shaped
steel sheet pile, rolling mills provided on the rolling line L and
so on. In FIG. 1, a rolling forward direction of the rolling line L
is a direction indicated with an arrow, the material to be rolled A
flows in the direction, rolling is performed in caliber rolling
mills (later-explained rough rolling mill, intermediate rolling
mill, and finish rolling mill) on the line to shape a product. Note
that a plurality of not-illustrated conveyor rolls are installed on
the rolling line L, and the material to be rolled A is conveyed on
the rolling line L by the conveyor rolls.
[0051] As illustrated in FIG. 1, on the rolling line L, a rough
rolling mill (BD) 17, a first intermediate rolling mill (R1) 18, a
second intermediate rolling mill (R2) 19, and a finish rolling mill
(F) 30 are arranged in order from the rolling upstream side.
[0052] On the rolling line L illustrated in FIG. 1, the material to
be rolled A such as a slab, bloom or the like heated in a
not-illustrated heating furnace (located on the upstream of the
rolling line L) is rolled in sequence in the rough rolling mill 17
to the finish rolling mill 30 to form into a hat-shaped steel sheet
pile being a final product.
[0053] Next, the shape of the caliber provided in any of the rough
rolling mill 17, the first intermediate rolling mill 18, the second
intermediate rolling mill 19, and the finish rolling mill 30
arranged on the rolling line L will be briefly explained in order
from the upstream side referring to the drawings. Note that in FIG.
2 to FIG. 6 referred to in the following explanation, the cross
section of the material to be rolled A when the reduction in each
caliber is completed is illustrated with one-dotted chain line for
reference.
[0054] FIG. 2 is a schematic cross-sectional view of the caliber
shape of the first caliber 49 (hereinafter, also described simply
as a caliber 49). As illustrated in FIG. 2, the caliber 49 is
composed of an upper caliber roll 45 and a lower caliber roll 48.
The caliber 49 composed of the upper caliber roll 45 and the lower
caliber roll 48 is provided, for example, in the rough rolling mill
17, and the caliber rolling in the caliber 49 performs the
thickness reduction (namely, rough rolling) on the whole material
to be rolled A. More specifically, the caliber rolling of making
the slab or the like heated to a predetermined temperature in the
heating furnace closer to the substantial hat shape is performed to
shape a raw blank A1 illustrated with a one-dotted chain line in
FIG. 2. Note that the rough rolling at this time may be performed,
for example, by reverse rolling in the same caliber 49.
[0055] Besides, FIG. 3 is a schematic cross-sectional view of the
caliber shape of a second caliber 59 (hereinafter, also described
simply as a caliber 59). As illustrated in FIG. 3, the caliber 59
is composed of an upper caliber roll 55 and a lower caliber roll
58. The caliber 59 composed of the upper caliber roll 55 and the
lower caliber roll 58 is provided, for example, in the first
intermediate rolling mill 18, and the caliber rolling in the
caliber 59 performs the thickness reduction (namely, first
intermediate rolling) on the whole material to be rolled A. In the
caliber 59, reduction of aligning the claw heights of the claw
parts 14, 15 to a desired height is also performed concurrently
with the thickness reduction, and more specifically, the caliber
rolling of making the raw blank A1 carried out of the caliber 49
much closer to the hat shape is performed. Thus, a first
intermediate material A2 illustrated with a one-dotted chain line
in FIG. 3 is shaped. Note that the rolling here is performed, for
example, by reverse rolling in the same caliber 59.
[0056] Besides, FIG. 4 is a schematic cross-sectional view
illustrating the caliber shape of a third caliber 69 (hereinafter,
also described simply as a caliber 69). As illustrated in FIG. 4,
the caliber 69 is composed of an upper caliber roll 65 and a lower
caliber roll 68. The caliber 69 composed of the upper caliber roll
65 and the lower caliber roll 68 is provided, for example, in the
second intermediate rolling mill 19, and the caliber rolling in the
caliber 69 performs the thickness reduction (namely, second
intermediate rolling) on the whole material to be rolled A. More
specifically, the caliber rolling of making the first intermediate
material A2 carried out of the caliber 59 much closer to the hat
shape is performed, and thereby a second intermediate material A3
illustrated with a one-dotted chain line in FIG. 4 is shaped. This
caliber 69 is in a shape having both end portions in the width
direction opened, so that the claw parts 14, 15 of the material to
be rolled A are in shapes extended in the width direction by the
thickness reduction. Note that the rolling here is performed, for
example, by reverse rolling in the same caliber 69.
[0057] FIG. 5 is a schematic cross-sectional view illustrating the
caliber shape of a fourth caliber 79 (hereinafter, also described
simply as a caliber 79). As illustrated in FIG. 5, the caliber 79
is composed of an upper caliber roll 75 and a lower caliber roll
78. The caliber 79 composed of the upper caliber roll 75 and the
lower caliber roll 78 is provided, for example, in the second
intermediate rolling mill 19, and the caliber 79 intensively
performs, for example, shaping of the claw parts 14, 15 of material
to be rolled A. More specifically, the reduction to perform the
forming while aligning the claw heights of the claw parts 14, 15 in
the state extended in the third caliber 69 to a desired height is
performed to shape a second intermediate material A4. Note that the
rolling here may be reduction of the thickness.
[0058] Besides, FIG. 6 is a schematic cross-sectional view
illustrating the caliber shape of a fifth caliber 89 (hereinafter,
also described simply as a caliber 89). As illustrated in FIG. 6,
the caliber 89 is composed of an upper caliber roll 85 and a lower
caliber roll 88. The caliber 89 composed of the upper caliber roll
85 and the lower caliber roll 88 is provided, for example, in the
finish rolling mill 30, and the caliber 89 mainly performs bending
forming (namely, finish rolling) of the claw parts 14, 15 on the
material to be rolled A. More specifically, the reduction of making
the second intermediate material A4 into a finished material A5 in
the substantial hat shape (substantially hat-shaped steel sheet
pile product shape). Note that, normally, the finish rolling is not
performed in reverse rolling but is performed by rolling in only
one pass.
[0059] Thus, the material to be rolled A is subjected to caliber
rolling in each rolling explained referring to FIG. 2 to FIG. 6,
and the finished material A5 is finally shaped.
[0060] Note that the configurations of the first caliber to the
fifth caliber described in the embodiment are examples and the
configurations are not limited to the illustrated forms, but, for
example, the arrangement order of the calibers, the caliber shape
arranged in each rolling mill, and the increased/decreased
arrangement of correction calibers for various calibers may be
changed as needed according to conditions such as the facility
status, product dimensions and so on. Further, depending on the
kind of the raw material, it is also conceivable to separately
provide a caliber such as a preform caliber used for rough shaping
process from the raw material.
[0061] According to the study of the present inventors, at an
intermediate rolling step by the caliber 59 and the caliber 69 in
the above production process, even when the rolling is performed
while balancing the elongation between the web corresponding part 3
and the flange corresponding parts 5, 6, the relative sliding speed
between the material to be rolled A (specifically, the flange
corresponding parts 5, 6) and the roll differs depending on a part
because the upper and lower caliber rolls are different in
diameters of upper and lower rolls depending on a part as
illustrated in FIG. 3 and FIG. 4. At the flange corresponding parts
5, 6, the elongation of the material to be rolled is suppressed by
a peripheral speed difference between the upper and lower rolls at
a part where the difference between upper and lower roll diameters
is large, whereas the elongation is likely to occur at a position
corresponding to a pitch line where the diameters of the upper and
lower rolls are equal (hereinafter, described a "neutral line"), so
that a compressive stress is likely to occur in the longitudinal
direction in the flange near the neutral line at a roll bite outlet
and, in the case where the compressive stress exceeds a buckling
limit, a defective shape so-called flange wave occurs at the flange
corresponding parts 5, 6.
[0062] In particular, in the production of a large-sized steel
sheet pile such as a hat-shaped steel sheet pile having a high
ratio of flange width/flange thickness, the elongation of the
flange near the neutral line tends to be large relative to the
elongation of the web, and the compressive stress in the
longitudinal direction acts on the middle parts of the flange
corresponding parts 5, 6 from the inside of the roll bite. Further,
the buckling limit stress also lowers, resulting in that the flange
wave is remarkably likely to occur.
[0063] In the case of performing rolling in one pass by the same
caliber, designing a caliber in a shape under consideration of the
flange elongation and the web elongation according to the relation
with the shape of the preceding caliber can suppress the flange
wave. However, it has been found that in the case of performing
rolling in two or more passes by the same caliber, each elongation
of the web corresponding part, the flange corresponding part and
the arm corresponding part is prescribed by the shape of the
caliber in the rolling in the second and subsequent passes, so that
it is impossible to suppress the occurrence of the flange wave in
the middle of the reverse rolling even if the shape of the caliber
is designed as in the prior art. For example, the result of study
has revealed that in the case where the reverse rolling is
performed in the calibers 59, 69, the metal gathers at the middle
parts (near the neutral line) of the flange corresponding parts 5,
6 every rolling at the flange corresponding parts 5, 6, and a
phenomenon of restoration of the flange thickness is likely to
occur. If the restoration of the thickness occurs, the flange
elongation increases in the next pass and the flange wave
undesirably becomes more likely to occur.
[0064] Besides, comparing the caliber 59 and the caliber 69, the
caliber 69 being a caliber at a subsequent stage rolls the material
to be rolled A (particularly, the flange corresponding parts 5, 6)
thinner, and therefore is more likely to remarkably cause a
defective shape such as the above-described occurrence of the
flange wave. Further, if the defective shape occurs, a step closer
to the finish rolling is more likely to be directly linked to the
product defective shape. In other words, it is important to solve
the problems as described above, in particular, in the caliber 69
being a caliber at a subsequent stage from the viewpoint of the
product dimension accuracy and the stability of rolling.
[0065] In view of the problems, the present inventors have
earnestly studied about the shapes of the calibers 59, 69 explained
referring to FIG. 3 and FIG. 4, and have arrived at the invention
of the caliber shape satisfying predetermined conditions causing no
defective shape called the flange wave. Hereinafter, the detailed
shape of a caliber 69' configured to cause no flange wave by
further improving the shape of the caliber 69 will be explained
referring to the drawings. Note that though the rolling and shaping
relating to, in particular, the flange corresponding part 6 of the
caliber 69' will be illustrated and explained as an example in the
following, the caliber of the object in the present invention is a
caliber for performing thickness reduction on the whole material to
be rolled A and is not limited to the calibers 59, 69.
[0066] FIG. 7 is a schematic explanatory view of the caliber 69' in
the configuration obtained by modifying the above third caliber 69,
and (a) illustrates a schematic entire view and (b) illustrates an
enlarged view near a place facing the flange corresponding part 6
(a portion surrounded by a broken line in FIG. 7(a)). Here, FIG.
7(b) illustrates an appearance after rolling in the caliber 69' and
illustrates the rolled material to be rolled A with a one-dotted
chain line. Note that in FIG. 7, the same codes are given to
components having the same functional configurations as those of
the caliber 69 explained referring to FIG. 4 to omit explanation
thereof.
[0067] In the modified caliber 69' illustrated in FIG. 7, a facing
portion 100 facing the flange corresponding part 6 of the material
to be rolled A is different in shape from that of the above caliber
69 and is concretely composed of a plurality of flange facing
portions 100a, 100b, 100c different in inclination in order to the
side closer to the web. Regarding the flange facing portions 100a,
100b, 100c, the flange facing portion 100b is prescribed and called
as a "first flange facing portion", and flange facing portions
100a, 100c arranged on both sides thereof are prescribed and called
a "second flange facing portion" and a "third flange facing
portion" respectively in some cases in this description. Further, a
part of the flange corresponding part 6 rolled and shaped by the
flange facing portion 100b located at the middle is prescribed and
called a "first flange part", and parts of the flange corresponding
part 6 arranged on both sides thereof (parts to be rolled and
shaped by the flange facing portions 100a, 100c) are prescribed and
called a "second flange part" and a "third flange part"
respectively in some cases.
[0068] Note that as illustrated in FIG. 7(a), a portion 101 facing
the flange corresponding part 5 of the material to be rolled A is
similarly composed of flange facing portions 101a, 101b, 101c.
[0069] Inclination angles of the flange facing portions 100a, 100b,
100c with respect to the horizontal line are .theta.f2, .theta.f1,
.theta.f3, respectively, and .theta.f1 is an angle larger than
.theta.f2 and .theta.f3. Besides, .theta.f2 and .theta.f3 may be an
equal angle. When intervals tf2, tf1, tf3 (called also as roll
gaps) between the upper caliber roll 65 and the lower caliber roll
68 in the flange facing portions 100a, 100b, 100c are constant (the
flange facing portions 100a, 100b, 100c of the upper caliber roll
65 and the lower caliber roll 68 are parallel), the angles
.theta.f2, .theta.f1, .theta.f3 in each of the upper caliber roll
65 and the lower caliber roll 68 are equal. On the other hand, when
the angles formed between the flange facing portions 100a, 100b,
100c and the horizontal line are different between the upper
caliber roll 65 and the lower caliber roll 68, it is only necessary
to regard average values of the angles formed between the flange
facing portions of the upper caliber roll 65 and the lower caliber
roll 68 and the horizontal line as the angles .theta.f2, .theta.f1,
.theta.f3. Further, the inclination angles .theta.f2, .theta.f1,
.theta.f3 are substantially the same even when prescribed as angles
formed between a center line S in the roll gap between the upper
and lower rolls and the horizontal line.
[0070] Further, the flange facing portion 100b is constituted at a
position across a neutral line O in the height direction, and the
flange facing portion 100a is located on the side closer to the web
than the flange facing portion 100b, and the flange facing portion
100c is located on the side closer to the arm (joint). In other
words, the flange facing portion 100b is located across the neutral
line O and the flange facing portions 100a, 100c are located on
both sides thereof.
[0071] Here, when the elongation per pass is defined by the
thickness ratio before rolling to the thickness after rolling
(after one pass), the thickness is represented by the roll gap in
the sheet thickness direction in the caliber 69', and a roll gap
reduction amount in the vertical direction in one pass during
reverse rolling in the caliber 69' is .DELTA.g, the elongations
.lamda.f1, .lamda.f2, .lamda.f3 per pass of the flange facing
portions 100b, 100a, 100c are expressed by following Expressions
(1) to (3).
.lamda.f1=tf1/tf1=(tf1+.DELTA.gcos .theta.f1)/tf1 (1)
.lamda.f2=tf2/tf2=(tf2+.DELTA.gcos .theta.f2)/tf2 (2)
.lamda.B=tf3/tf3=(tf3+.DELTA.gcos .theta.f3)/tf3 (3)
Note that tf1, tf2, tf3 are roll gaps corresponding to the
thickness before rolling of the flange corresponding part 6
corresponding to the flange facing portions 100b, 100a, 100c in the
caliber 69'. Further, tf1, tf2, tf3 are roll gaps corresponding to
the thicknesses of the flange corresponding part 6 rolled by the
flange facing portions 100b, 100a, 100c respectively in the caliber
69'.
[0072] Specifically, by making .theta.f1 a larger angle than
.theta.f2 and .theta.f3 based on the relation among tf1, tf2, tf3,
the following Expressions (4), (5) are satisfied in rolling in the
caliber 69'.
.lamda.f1<.lamda.f2 (4)
.lamda.f1<.lamda.f3 (5)
Here, the above Expressions (1) to (3) express the elongations per
pass of rolling, and the relations similar to Expressions (1) to
(3) are established also in the case of totaling the elongations in
the reverse rolling performed in a plurality passes. Accordingly,
by making .theta.f1 a larger angle than .theta.f2 and .theta.f3 in
the caliber 69', the above Expressions (4), (5) are satisfied not
only in the case of the elongations per pass but also in the case
of totaling the elongations in a plurality passes during the
reverse rolling.
[0073] The material to be rolled A rolled and shaped in the caliber
69' becomes a bent shape having a plurality of inclination angles
at the flange corresponding part 5, 6. This shape is made into a
desired flat flange shape (flange shape of the hat-shaped steel
sheet pile product) by the caliber at a stage subsequent to the
caliber 69' provided in the intermediate rolling mill, for example,
the fourth caliber 79, the fifth caliber 89 in the finish rolling
mill 30 (finish rolling step) or both of the calibers. In the
flange flattening, no reverse rolling is performed. Note that after
the bending-back of the flange part, streaky traces in the
longitudinal direction are found in the boundary portion of the
bent part due to the difference in adherence state of scale with
respect to other portions or the like, but the traces do not reduce
the strength or the like of the flange part and do not affect the
quality as the steel sheet pile.
[0074] According to the caliber configuration as illustrated in
FIG. 7, making the angle On large decreases the flange elongation
near the neutral line O where the compressive stress is likely to
occur relative to the caliber 69 having the linear flange facing
portion as illustrated in FIG. 4 and decreases the flange
elongation near the neutral line O relative to the flange
elongation at a position separated from the neutral line O to
thereby realize the effect of suppressing the occurrence of the
flange wave. On the other hand, making the angles .theta.f2 and
.theta.f3 small suppresses the increase in flange height to thereby
maintain the elongation of the cross section of the flange
corresponding part 6. For example, it is only necessary to make the
line length of the center line S corresponding to the flange facing
portions (100a, 100b, 100c) of the caliber 69' identical to the
line length of the center line of the flange facing portions of the
caliber 69 and design the angles .theta.f2, .theta.f3 in a manner
not to change the position in the horizontal direction of the joint
with respect to the angle On decided as a flange wave suppression
condition, in consideration of the suppression of variation in
dimension when shaping into a desired flat flange shape by rolling
by the caliber at a subsequent stage. In other words, if the
reverse rolling is performed in the modified caliber 69', the
flange elongation decreases as compared with the caliber 69
illustrated in FIG. 4 in the flange facing portion 100b but the
flange elongation increases as compared with the caliber 69 at the
flange facing portions 100a, 100c, and therefore the same flange
cross section elongation as that in the caliber 69 can be
maintained as the whole flange. Note that making the line length of
the center line S corresponding to the flange facing portions
(100a, 100b, 100c) of the caliber 69' identical to the line length
of the center line of the flange facing portions of the caliber 69
does not mean being complete identical but may be being identical
within a range of error (for example, less than .+-.1% with respect
to the line length of the center line of the flange facing
portion).
[0075] Here, to suppress the flange wave at the flange facing
portion 100b (hereinafter, referred to also as a steep inclination
part 100b) near the neutral line O, it is preferable to set the
angle .theta.f1 so that the relation between the elongation
.lamda.f1 of the flange at the steep inclination part 100b and a
elongation .lamda.w of the web corresponding part 3 satisfies the
following Expression (6).
.lamda.f1<.lamda.w (6)
Note that it is preferable to set .lamda.f1/.lamda.w per pass to
fall within a range of
0.967.ltoreq..lamda.f1/.lamda.w.ltoreq.1.000, as a more detailed
condition. The basis of the numeral values will be explained in
later-described examples.
[0076] Since the elongation of the flange is greatly affected by
the elongation of the web, the elongation of the flange
corresponding part near the neutral line O is expressed by the
relation with the elongation of the web also in the technique of
the present invention. In the case of the hat-shaped steel sheet
pile, the elongation of the arm corresponding parts 8, 9 and the
elongation of the web corresponding parts 5, 6 are considered to be
substantially equal, and since the U-shaped steel sheet pile has no
arm corresponding part, the elongation of the flange corresponding
part near the neutral line O can be substantially expressed by the
relation with the web elongation. The elongation .lamda.w of the
web in one pass during reverse rolling is expressed by the
following Expression (7).
.lamda.w=tw'/tw=(tw+.DELTA.gcos .theta.w)/tw (7)
Here, tw' is the roll gap corresponding to the thickness of the web
corresponding part 3 before rolling in the caliber 69'. Besides, tw
is the roll gap corresponding to the thickness of the web
corresponding part 3 rolled in the caliber 69'. Besides, .theta.w
is the inclination angle of the roll gap corresponding to the web
corresponding part 3 with respect to the horizontal line.
[0077] Further, in the case of the hat-shaped steel sheet pile
having a constant thickness in the flange width direction, the
caliber shape is designed so that each thickness of the flange
facing portions 100a, 100b, 100c is constant in the final pass
except the error accompanying roll abrasion or the like in the
caliber 69' directly before the finish rolling, but the inclination
angle .theta.f1 of the flange facing portion 100b is different from
the inclination angles .theta.f2, .theta.f3 of the flange facing
portions 100a, 100c, and therefore each thickness is not constant
in midway passes in the caliber 69'. For this reason, the
inclination angle and the width of each flange facing portion may
be decided in consideration of the elongation ratios
.lamda.f1/.lamda.w, .lamda.f2/.lamda.w, .lamda.f3/.lamda.w in a
pass where the flange wave is most likely to occur from the
relation between the thickness and elongation of each flange facing
portion and the elongation of the web corresponding part.
[0078] As explained above, making the inclination angle .theta.f1
of the steep inclination part 100b large makes it possible to
decrease the flange elongation near the neutral line O and reduce
the compressive stress occurring at this portion.
[0079] Making the caliber shape of the caliber 69' provided in the
second intermediate rolling mill 19 in the shape having the
plurality of flange facing portions 100a, 100b, 100c different in
inclination as explained above referring to FIG. 7 and setting the
inclination angles of the flange facing portions 100a, 100b, 100c
to preferable conditions as expressed in the above Expressions (1)
to (6) make it possible to reduce the compressive stress occurring
near the neutral line O of the flange corresponding part 6 in the
rolling and shaping in the caliber 69' and suppress the occurrence
of the flange wave. Furthermore, it is also possible to reduce the
restoration of the flange thickness occurring due to gathering of
the metal near the neutral line of the flange corresponding part 6
in the reverse rolling to further suppress the occurrence of the
flange wave.
[0080] On the other hand, the elongation of the flange occurring at
the flange facing portions 100a and 100c increases relative to the
elongation of the flange occurring near the neutral line O (namely,
the elongation of the flange at the flange facing portion 100b) and
the compressive stress occurring there also increases, but the
compressive stress does not become excessive since metal flow to
the web corresponding part 3 and the arm corresponding part 9 is
likely to occur in addition to separation from the neutral line O.
Further, parts, corresponding to the flange facing portions 100a
and 100c, in the flange corresponding part 6 are connected to the
web corresponding part 3 and the arm corresponding part 9 and
unlikely to cause buckling, so that the flange wave is unlikely to
occur at the parts.
[0081] As described above, making the caliber shape of the caliber
69' in the shape having the plurality of flange facing portions
100a, 100b, 100c different in inclination angle makes it possible
to suppress the flange wave occurring near the neutral line O of
the flange corresponding parts 5, 6 of the material to be rolled A
as compared with the rolling and shaping in the conventional
caliber shape (caliber 69) as illustrated in FIG. 4, thereby
realizing the improvement of the product dimension accuracy and the
stability of rolling. Depending on the product shape, the
elongation of the flange corresponding parts 5, 6 is larger than
the elongation of the web corresponding part 3 in the conventional
caliber shape (caliber 69) as illustrated in FIG. 4, so that the
balance cannot be maintained any longer and the flange wave cannot
be suppressed in some cases. In this case, not changing the
inclination angle of the whole flange but making the inclination
angle .theta.f1 of the steep inclination part 100b larger than the
flange inclination angle of the conventional caliber shape as
illustrated in FIG. 7 and larger than the flange facing portions
100a and 100c makes it possible to suppress the increase in height
of the material to be rolled A during the rolling and shaping and
effectively suppress the flange wave.
[0082] One example of the embodiment of the present invention has
been explained above, but the present invention is not limited to
the illustrated embodiment. It should be understood that various
changes and modifications are readily apparent to those skilled in
the art within the scope of the spirit as set forth in claims, and
those should also be covered by the technical scope of the present
invention.
[0083] For example, the technique of the present invention is
applied in the above embodiment, and the explanation has been made
using the third caliber 69 as the object to be modified in caliber
shape and especially the rolling and shaping of the flange
corresponding part 6 of the material to be rolled A has been
explained referring to FIG. 7, but the application range of the
present invention is not limited to this. More specifically, the
technique of the present invention is obviously applicable to both
of the flange corresponding parts 5, 6 in the rolling and shaping
in the third caliber 69 and also to the rolling and shaping in the
second caliber 59. More specifically, the same modification can be
applied also to the caliber 59 explained referring to FIG. 3 to
suppress, for example, the flange wave occurring in the first
intermediate rolling. Further, as a matter of course, the technique
of the present invention may be applied to the caliber shapes of
both of the second caliber 59 and the third caliber 69.
Alternatively, regarding the second caliber 59 and the third
caliber 69 for mainly reducing the thickness, the same modification
may be applied also to the case where the second caliber 59 is made
into a caliber shape having both end portions in the width
direction opened and the third caliber 69 is made into a caliber
shape for simultaneously performing the shaping of the claw height.
Furthermore, the technique of the present invention may be applied
to the first caliber for performing the rough rolling.
[0084] Further, though the caliber shape of the caliber 69' is
explained as a shape having the plurality of flange facing portions
100a, 100b, 100c different in inclination angle in the above
embodiment, the important point of the technique of the present
invention is to make the inclination angle .theta.f1 of the flange
facing portion 100b near the neutral line O larger than those of
the other flange facing portions in the caliber for performing the
intermediate rolling so as to reduce the compressive stress acting
on the material to be rolled A near the neutral line O. From the
viewpoint, in the case of constituting the caliber of the
intermediate rolling mill in a shape having the plurality of flange
facing portions different in inclination angle in the technique of
the present invention, it is not always to provide the three flange
facing portions as illustrated in FIG. 7, but any number of flange
facing portions different in inclination angle may be provided as
long as the inclination angle .theta.f1 of the flange facing
portion 100b near the neutral line O is larger than those of the
other flange facing portions. In short, for example as illustrated
in FIG. 10, the caliber for performing the intermediate rolling may
be configured to have four or more flange facing portions different
in inclination angle.
[0085] Further, the caliber part facing the flange corresponding
part 5, 6 of the material to be rolled A (namely, the flange facing
portion 100) may be, with respect to a straight line linking the
boundary part on the arm side (of the material to be rolled) and
the boundary part on the web side (of the material to be rolled),
in a protruding shape in a flange inside direction on the side
closer to the arm than the flange facing portion near the neutral
line O and in a protruding shape in a flange outside direction on
the side closer to the web than the flange facing portion near the
neutral line O.
[0086] Specifically, regarding the shape of the flange facing
portion 100 provided with the steep inclination part 100b explained
in the above embodiment, the shape of each of the flange facing
portions 100a to 100c does not always need to be formed in the
linear shape but, for example, part or all of the flange facing
portions 100a to 100c may be formed by a curved line as long as the
inclination angles of the flange facing portions 100a, 100b, 100c
are made under the preferable conditions as expressed in the above
Expressions (4) to (6). In this case, the steep inclination part
100b is defined as a range sandwiched between an intersection with
the flange facing portion 100a and an intersection with the flange
facing portion 100c, and the steep inclination part 100b is
configured to cross the neutral line O.
[0087] FIG. 8 is a schematic explanatory view according to a
modification example of the present invention and is a schematic
enlarged view illustrating an example of the vicinity of a place
facing the flange corresponding part 6. As illustrated in FIG. 8,
in this modification example, the flange facing portions 100a, 100c
are formed in a curved shape. The step of performing the reverse
rolling, including other embodiments, preferably includes a step of
forming the web corresponding part 3 connected to the flange part
including at least one second flange part (referred to also as a
web-side flange part) and the arm corresponding part 9 connected to
the flange part including at least one third flange part (referred
to also as an arm-side flange part). In this case, the caliber
according to the present invention preferably includes a web facing
portion 100d for forming the web corresponding part 3 and an arm
facing portion 100e for forming the arm corresponding part 9. Here,
the caliber preferably includes a web-side flange facing portion
group including at least one flange facing portion 100a (second
flange facing portion) and an arm-side flange facing portion group
including at least one flange facing portion 100c (third flange
facing portion). Here, the boundary between the web-side flange
facing portion group and the web facing portion 100d is assumed to
be Pa, and the boundary between the arm-side flange facing portion
group and the arm facing portion 100e is assumed to be Pc. In the
example illustrated in FIG. 8, with respect to a straight line Q
linking the boundary part Pc on the arm side (the boundary between
the arm facing portion 100e facing the arm corresponding part 9 and
the flange facing portion 100c) and the boundary part Pa on the web
side (the boundary between the web facing portion 100d facing the
web corresponding part 3 and the flange facing portion 100a in the
caliber 65), the flange facing portion 100a is in a curved shape to
be a protruding shape in a flange outside direction, and the flange
facing portion 100c is in a curved shape to be a protruding shape
in a flange inside direction. Further, the steep inclination part
100b is illustrated as a linear shape in this modification example,
but the steep inclination part 100b may be in a curved shape.
[0088] In the case where the flange facing portions 100a, 100c as
illustrated in FIG. 8 are in a curved shape, the inclination angles
.theta.f2, .theta.f3 of the flange facing portions 100a, 100c only
need to be decided by the inclination angles of the tangents (Qa,
Qc in FIG. 8) at the middle part in the height direction of the
flange facing portions 100a, 100c with respect to the horizontal
line. In the case where the steep inclination part 100b is in a
curved shape, the inclination angle only needs to be decided based
on the tangent where the angle becomes maximum. The straight line Q
and the tangents Qa, Qc are explained using the lower caliber roll
68 in FIG. 8, and those only need to be similarly decided also in
the upper caliber roll 65. Then, in the case where the angles
formed between the flange facing portions 100a, 100b, 100c and the
horizontal line are different between the upper caliber roll 65 and
the lower caliber roll 68, .theta.f2, .theta.f2, .theta.f3 only
need to be set to average values of the angles formed between the
flange facing portions of the upper caliber roll 65 and the lower
caliber roll 68 and the horizontal line. By setting the inclination
angles of the flange facing portions 100a to 100c defined as
described above to the preferable conditions as expressed in the
above Expressions (1) to (6) similarly to the above embodiment, the
same operation and effect can be obtained.
[0089] More specifically, in the above embodiment, the caliber
shape of the modified caliber 69' is explained as a shape having
the plurality of flange facing portions 100a, 100b, 100c different
in inclination angle, but the detailed shapes of the portions 100a,
100b, 100c are not mentioned. The shape of the flange corresponding
part 5, 6 only needs to be constituted by a plurality of straight
lines or curved lines or combination of them, and the shapes of the
portions 100a, 100b, 100c can be arbitrarily designed according to
the shape of the flange corresponding part 5, 6. If the curved
portion is constituted in the flange corresponding part 5, 6, the
inclination angle of the curved portion only needs to be defined by
the angle of its tangent.
[0090] Further, it is extremely effective to apply the technique of
the present invention to a product in which the flange
corresponding part has a thickness distribution that the thickness
changes in a direction along the surface of the flange
corresponding part or to a product in a shape having a plurality of
bent portions in which the flange corresponding part increases in
inclination angle near the neutral line, which falls within the
scope of the present invention. In the case where the flange
corresponding part has the thickness distribution in a direction
along its surface, it is conceivable to relatively decrease the
thickness near the neutral line based on the cross-sectional
efficiency of the hat-shaped steel sheet pile product. When
applying the technique of the present invention to the above case,
the elongation of the flange in the flange facing portion 100b is
unlikely to become larger than that in the conventional caliber
shape because the inclination angle of the flange facing portion
100b is larger than the those of the flange facing portions 100a,
100c, so that the operation and effect equal to or more than those
in the above embodiment can be obtained. Further, the rolling
states in the bent shapes illustrated in FIG. 7 and FIG. 8 can be
applied also to the steel sheet pile product in which the flange is
bent to increase in inclination angle near the neutral line in the
product shape, which is very useful.
[0091] Further, in the caliber shape of the caliber 69', the
boundary parts between the flange facing portions 100a, 100b, 100c
may have R. In this case, each boundary between the flange facing
portions 100a, 100b, 100c only needs to be an intermediate point of
a corner R.
[0092] Furthermore, as a result of detailed study by the present
inventors, it has been revealed that the flange wave occurring in
the conventional caliber 69 has a peak position of the wave height
in the cross section of the flange corresponding part included in a
range of 10% of a caliber depth D in the height direction from the
neutral line O of the caliber 69 illustrated in FIG. 4.
[0093] Therefore, in the case where the steep inclination part 100b
near the neutral line O is linear, it is desirable that the steep
inclination part 100b decreasing the flange elongation includes the
range of 10% of the caliber depth D in the height direction upward
and downward from the neutral line O as illustrated in FIG. 11.
Further, when a center point position Fc of a line segment in the
steep inclination part 100b of the center line S coincides with the
neutral line O, the operation and effect explained in the above
embodiment can be remarkably obtained. Note that the caliber depth
D is defined by the height in the vertical direction of the whole
flange facing portions (100a, 100b, 100c) of the lower caliber roll
forming the caliber, and the upper end position of the caliber
depth D is the upper end in the height direction of the boundary
between the flange corresponding part and the arm corresponding
part, and the lower end position is the lower end in the height
direction of the boundary between the flange corresponding part and
the web corresponding part as illustrated in FIG. 11.
[0094] Further, also in the case where the flange facing portion
100b near the neutral line O is curved or a combination of a
plurality of line segments, it is desirable that the steep
inclination part 100b (a range of P1 to P2 in the elongation)
includes the range of 10% of the caliber depth D in the height
direction upward and downward from the neutral line O as
illustrated in FIG. 12. In these cases, when a position Fd where
the angle with respect to the horizontal line becomes maximum in
the line segment corresponding to the steep inclination part 100b
of the center line S coincides with the neutral line O, the
above-described effect is further remarkable. However, as
illustrated in FIG. 12, even if the position Fd deviates in the
height direction from the neutral line O as long as it is within
the range of 10% of the caliber depth D, the effect of the present
invention can be provided. This is because of the same reason as
that in the case where the flange facing portion 100b is linear. In
this case, it is only necessary to set the inclination angle at the
position of the maximum inclination angle to .theta.f2 and set the
flange elongation to .lamda.1. Accordingly, these cases are also
regarded as being near the neutral line O and fall within the scope
of the present invention.
[0095] Note that the case where the second flange facing portion
and the third flange facing portion are arranged adjacent to the
first flange facing portion is explained in the above embodiment
and other embodiments, but they do not always need to be adjacently
arranged. In other words, the second flange facing portion and the
third flange facing portion are smaller in inclination angle than
the first flange facing portion, and can also be set according to
the product shape between the first flange facing portion and the
web facing portion and between the first flange facing portion and
the arm facing portion, respectively.
[0096] Further, the above embodiment and other embodiments have
been illustrated and explained using the case of rolling the
hat-shaped steel sheet pile as an example, but the application
range of the present invention is not limited to them. In other
words, the present invention is applicable to steel sheet piles
with flanges in various shapes where the flange wave possibly
occurs in the intermediate rolling. More specifically, the present
invention is applicable to a U-shaped steel sheet pile in addition
to the hat-shaped steel sheet pile.
EXAMPLES
Example 1
[0097] As Example 1 of the present invention, a caliber
corresponding to the modified caliber 69' above explained referring
to FIG. 7 was applied to the intermediate rolling caliber (the
second caliber and the third caliber in the above embodiment), and
the rolling and shaping was performed on the material to be rolled
under the conditions 1 to 5 listed in the following Table 1.
[0098] The flange facing portion of the caliber was configured to
be bent to three portions such that the first flange part crossed
the neutral line of the calibers indicated in the conditions 1 to
5. Here, the angle and the length of each flange facing portion
were adjusted. Further, the flange facing portion of the material
to be rolled after the rolling and shaping was flattened in the
calibers at the subsequent stages (the fourth caliber and the fifth
caliber in the above embodiment).
[0099] Further, as comparative examples, the conventional caliber
(a caliber corresponding to the caliber 69 before modification) was
applied to the intermediate rolling caliber, and the rolling and
shaping was performed on the material to be rolled under the
conditions 6, 7 listed in the following Table 1.
[0100] The rolling and shaping in the caliber under each of the
conditions indicated in the conditions 1 to 7 is performed in a
plurality of passes, and the flange/web elongation ratios
.lamda.f1/.lamda.w, .lamda.f2/.lamda.w, .lamda.f3/.lamda.w listed
in Table 1 are elongation ratios per pass of the rolling and
shaping in the plurality of passes. Note that in the examples and
comparative examples, the flange angle .theta.f of the hat-shaped
steel sheet pile product as the final product to be produced was
set to 48.degree.. FIG. 9 is an explanatory view of this example,
and is a schematic cross-sectional view illustrating an appearance
of the final pass of the rolling and shaping in the third caliber
according to the example. Note that FIG. 9 illustrates, using a
broken line, the shape of the flange facing portion having a flange
angle .theta.f=48.degree. similar to the final product. The values
of codes .theta.f1, .theta.f2, .theta.f3 listed in Table 1 are
values at places illustrated in FIG. 9.
TABLE-US-00001 TABLE 1 PRODUCT FLANGE FLANGE ANGLE(.degree.)
.lamda.f2/.lamda.w CONDITION THICKNESS(mm) .theta.f1 .theta.f2
.theta.f3 .lamda.f1/.lamda.w .lamda.f3/.lamda.w RESULT 1 PRESENT
6.5 66 44 44 0.967 1.020 NO FLANGE INVENTION WAVE OCCURRED 2
PRESENT 6.5 60 45 45 0.985 1.018 NO FLANGE WAVE INVENTION OCCURRED
3 PRESENT 6.5 56 42 42 0.995 1.023 NO FLANGE WAVE INVENTION
OCCURRED 4 PRESENT 6.5 54 45 45 1.000 1.018 NO FLANGE WAVE
INVENTION OCCURRED 5 PRESENT 6.5 52 45 45 1.004 1.018 LITTLE FLANGE
INVENTION WAVE DURING INTERMEDIATE ROLLING (NO FLANGE WAVE ON
PRODUCT) 6 CONPARATIVE 6.5 48 1.013 FLANGE WAVE EXAMPLE OCCURRED 7
CONPARATIVE 7.7 48 0.995 FLANGE WAVE EXAMPLE OCCURRED
[0101] As listed in Table 1, under the conditions 1 to 5, the
values of angles .theta.f1, .theta.f2, .theta.f3 were changed as in
Table 1 when forming the steep inclination part in the caliber and
the intermediate rolling was performed under each of the
conditions. Then, the flange corresponding part of the material to
be rolled subjected to the rolling and shaping under of each of the
conditions was then shaped into a linear shape (flat shape) in the
rolling mill at the subsequent stage, and the defective shape such
as the presence or absence of the occurrence of the flange wave was
confirmed.
[0102] Under the conditions 1 to 5, the steep inclination part
having .theta.f1>.theta.f2, .theta.f1>.theta.f3 was formed in
the caliber, resulting in .lamda.f1<.lamda.f2,
.lamda.f1<.lamda.f3, and the value of .lamda.f1/.lamda.w is
0.967 to 1.004. Under the above condition, the flange elongation at
the steep inclination part was reduced to suppress the occurrence
of the flange wave. Regarding the conditions 1 to 4, the value of
.lamda.f1/.lamda.w is 0.967 to 1.000 so as to satisfy the above
Expression (6), thus it was confirmed that there was no occurrence
of the flange wave from the intermediate rolling time. Further,
regarding the condition 5, the value slightly deviated from the
range of the above Expression (6), little flange wave was confirmed
in some passes during the intermediate rolling time, but no flange
wave was confirmed in the product passed through the rolling at the
subsequent stage and the like, and thus sufficient effect was
confirmed.
[0103] On the other hand, under the condition 6 (comparative
example), the rolling and shaping was performed without forming the
steep inclination part in the caliber, resulting in flange
elongation .lamda.f1>web elongation .lamda.w, and the rolling
and shaping was rolling and shaping not satisfying the Expression
(6) explained in the above embodiment, in which the occurrence of
the flange wave was confirmed.
[0104] Further, under the condition 7 (comparative example), the
flange thickness of the product was increased by 1.2 mm and rolling
was performed under the condition of the value of
.lamda.f1/.lamda.w of 0.995 to satisfy the Expression (6), but the
rolling and shaping was performed without forming the steep
inclination part as in the condition 6, and thus the occurrence of
the flange wave was confirmed.
[0105] In short, in the comparative examples under the conditions
6, 7, the rolling and shaping was performed without forming the
steep inclination part in the caliber under the condition that the
inclination angle of the flange part was constant at any position,
and thus the elongation was different depending on the position
(part) of the flange part and the flange wave occurred.
[0106] From the above, it is found that bending the flange facing
portion of the caliber into three portions suppresses the
occurrence of the flange wave to enable the production in a size
with small flange thickness.
INDUSTRIAL APPLICABILITY
[0107] The present invention is applicable to a production
technique of a steel sheet pile having a flange such as a
hat-shaped steel sheet pile, a U-shaped steel sheet pile and the
like.
EXPLANATION OF CODES
[0108] 1 . . . rolling facility [0109] 3 . . . web corresponding
part [0110] 5, 6 . . . flange corresponding part [0111] 8, 9 . . .
arm corresponding part [0112] 10, 11 . . . joint corresponding part
[0113] 14, 15 . . . claw part [0114] 17 . . . rough rolling mill
[0115] 18 . . . first intermediate rolling mill [0116] 19 . . .
second intermediate rolling mill [0117] 30 . . . finish rolling
mill [0118] 45 . . . upper caliber roll (of first caliber) [0119]
48 . . . lower caliber roll (of first caliber) [0120] 49 . . .
first caliber [0121] 55 . . . upper caliber roll (of second
caliber) [0122] 58 . . . lower caliber roll (of second caliber)
[0123] 59 . . . second caliber [0124] 65 . . . upper caliber roll
(of third caliber) [0125] 68 . . . lower caliber roll (of third
caliber) [0126] 69 . . . third caliber [0127] 69' . . . modified
third caliber [0128] 75 . . . upper caliber roll (of fourth
caliber) [0129] 78 . . . lower caliber roll (of fourth caliber)
[0130] 79 . . . fourth caliber [0131] 85 . . . upper caliber roll
(of fifth caliber) [0132] 88 . . . lower caliber roll (of fifth
caliber) [0133] 89 . . . fifth caliber [0134] 100 . . . facing
portion [0135] 100a to 100c . . . flange facing portion [0136] 101a
to 101c . . . flange facing portion [0137] A (A1 to A5) . . .
material to be rolled [0138] L . . . rolling line [0139] O . . .
neutral line
* * * * *