U.S. patent application number 11/577882 was filed with the patent office on 2009-05-21 for molten metal feed nozzle.
This patent application is currently assigned to Ishikawajima-Harima Heavy Industries Co.,Ltd. Invention is credited to Hisahiko Fukase, Akihiko Kimatsuka, Rama Mahapatra, Shiro Osada, Hiroyuki Otsuka, Peter Woodberry, Hiroki Yoshizawa.
Application Number | 20090126895 11/577882 |
Document ID | / |
Family ID | 36227699 |
Filed Date | 2009-05-21 |
United States Patent
Application |
20090126895 |
Kind Code |
A1 |
Otsuka; Hiroyuki ; et
al. |
May 21, 2009 |
MOLTEN METAL FEED NOZZLE
Abstract
A nozzle end is provided with an extension 11 which has a lower
portion immersed in a molten metal pool and extends toward a side
weir 2 such that a stagnation area disappears on a free liquid
surface of molten metal. The extension 11 is in the form of a
quadrangular pyramid lying sidelong and is converged to a point P1
extremely close to the side weir 2. According to this molten metal
feed nozzle, a stagnation area on a free liquid surface of molten
metal is displaced by the extension 11 contiguous with the nozzle
end to suppress generation of an unwanted solidification shell.
Thus, no unwanted solidification shell is pinched as foreign matter
by solidification shells generated on outer peripheries of chilled
rolls 1 for production of a strip and break of a strip derived from
enlargement of nip between the rolls can be averted.
Inventors: |
Otsuka; Hiroyuki; (Tokyo,
JP) ; Kimatsuka; Akihiko; (Tokyo, JP) ; Osada;
Shiro; (Tokyo, JP) ; Yoshizawa; Hiroki;
(Tokyo, JP) ; Fukase; Hisahiko; (Tokyo, JP)
; Mahapatra; Rama; (New South Wales, AU) ;
Woodberry; Peter; (New South Wales, AU) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
Ishikawajima-Harima Heavy
Industries Co.,Ltd
Tokyo
JP
|
Family ID: |
36227699 |
Appl. No.: |
11/577882 |
Filed: |
October 20, 2005 |
PCT Filed: |
October 20, 2005 |
PCT NO: |
PCT/JP05/19282 |
371 Date: |
October 29, 2007 |
Current U.S.
Class: |
164/428 |
Current CPC
Class: |
B22D 11/0642
20130101 |
Class at
Publication: |
164/428 |
International
Class: |
B22D 11/10 20060101
B22D011/10; B22D 11/06 20060101 B22D011/06 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 27, 2004 |
JP |
2004-311962 |
Claims
1. A molten metal feed nozzle positioned above a nip between rolls
of a twin roll caster and having ends spaced apart from side weirs,
comprising extensions each contiguous with the nozzle end and
extending toward the side weir such that a stagnation area
disappears on a free liquid surface of molten metal.
2. A molten metal feed nozzle as claimed in claim 1, wherein the
extension is converged toward the side weir.
3. A molten metal feed nozzle as claimed in claim 1, wherein the
extension is converged to a point extremely close to the side weir.
Description
TECHNICAL FIELD
[0001] The present invention relates to a molten metal feed nozzle
incorporated in a twin roll caster
BACKGROUND ART
[0002] FIG. 1 shows an example of a twin roll caster with a pair of
chilled rolls 1 arranged horizontally and in parallel with each
other and a pair of side weirs 2 associated with the chilled rolls
1.
[0003] The rolls 1 through which cooling water flows interiorly are
adapted to increase or decrease a nip or gap G between the rolls
depending upon thickness of a strip 3 to be produced
[0004] Rotational directions and velocities of the rolls 1 are set
such that respective outer peripheries of the rolls are moved from
above toward the nip G at constant velocity.
[0005] One and the other of the side weirs 2 are urged to
surface-contact one and the other ends of the rolls 1,
respectively. In a space surrounded and defined by the side weirs 2
and rolls 1, a molten metal feed nozzle made of refractory is
positioned just above the nip P between the rolls.
[0006] The feed nozzle has an elongated nozzle trough 5 which in
turn has a top opened for reception of molten metal 4 and
longitudinal side walls formed at their lower ends with a plurality
of openings 6 for passage from the trough 5 to the outer
peripheries of the rolls 1, the openings being spaced apart from
each other axially of the rolls. By pouring the molten metal 4 into
the nozzle trough 5, a molten metal pool 7 is formed above the nip
G between the rolls and in contact with the outer peripheries of
the rolls 1.
[0007] More specifically, when the molten metal pool 7 is formed
and the rolls l chilled by passage of the cooling water are
rotated, the molten metal 4 is solidified on the outer peripheries
of the rolls 1 and the strip 3 is delivered downwardly from the nip
G between the rolls.
[0008] Since wear on sliding portions of the side weirs relative to
the rolls 1 progresses in direct proportion to accumulative
operational time period, force for urging the side weirs 2 against
the rolls 1 is gradually increased to prevent leakage of the molten
metal 4 from between such members.
[0009] Molten metal feed nozzles incorporated in twin roll casters
may be divided into those with ends of the nozzle which
surface-contact the side weirs 2 (see, for example, Reference 1)
and those with ends of the nozzle which are spaced apart from and
in parallel with the side weirs 2 sees for example, Reference
2).
[Reference 1] JP 62-45456A
[Reference 2] JP 6-114505A
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0010] However, in application of a structure in Reference 1, the
molten metal feed nozzle remains unchanged in its longitudinal
size. Thus, as the wear on the sliding portion of the side weir 2
progresses, leakage of the molten metal 4 becomes unsuppressed by
merely increasing the force for urging the side weirs 2 to the
rolls 1.
[0011] In application of a structure in Reference 2, as shown in
FIG. 10, flow velocity distribution at free liquid surface of the
molten metal 4 tends to be low at between two parallel surfaces
facing to each other i.e., a surface 9 of the side weir on the
molten metal pool and an end wall surface 10 of the molten metal
nozzle, in comparison with at between a longitudinal side wall
surface 8 of the molten metal nozzle and the chilled roll 1. As a
result, an area A where the molten metal 4 tends to stagnate is
formed especially from the end wall surface 10 to a point P0 which
is an intersection of nip center line L with the surface 9 of the
side weir.
[0012] It occurs in the stagnation area A that the molten metal 4
is lowered in temperature due to radiation heat transmission and a
solidification shell is generated which is unwanted for the free
liquid surface of the molten metal 4 and for the end wall surface
10 of the nozzle.
[0013] When such unwanted solidification shell is pinched as
foreign matter by the solidification shells generated on the outer
peripheries of the chilled rolls 1 upon rotation of the rolls, the
strip 3 may be locally thickened into defective shape and/or the
nip G between the rolls may be enlarged depending upon part of the
strip 3 where the foreign matter is pinched, resulting in break of
the strip 3 due to reduction in cooling efficiency and heat
recuperation from the molten metal 4.
[0014] The invention was made in view of the above and has its
object to provide a molten metal feed nozzle which can avert break
of a strip
Means or Measures for Solving the Problems
[0015] In order to attain the above object, the invention is
directed to a molten metal feed nozzle positioned above a nip
between rolls of a twin roll caster and having ends spaced apart
from side weirs comprising extensions each contiguous with the
nozzle end and extending toward the side weir such that a
stagnation area disappears on a free liquid surface of molten
metal.
[0016] In the invention, the extensions eliminate stagnation areas
of the free liquid surface of the molten metal; they prevent the
molten metal from being lowered in temperature due to radiation
heat transmission and suppress generation of unwanted
solidification shells.
EFFECTS OF THE INVENTION
[0017] According to a molten metal feed nozzle of the invention,
the following excellent effects and advantages can be obtained.
[0018] (1) The extensions prevent the molten metal adjacent to the
side weirs from being lowered in temperature and suppress
generation of solidification shells on the free liquid surface of
the molten metal, so that unwanted solidification shells are not
pinched as foreign matter by the solidification shells generated on
the outer peripheries of the chilled roll for production of the
strip, and thus break of the strip derived from enlargement of the
nip between the rolls can be averted.
[0019] (2) When the extensions are shaped to be converged toward
the side weirs for gradual reduction in volume of the extensions,
heat transmission from the molten metal to the extensions is
reduced so that the molten metal adjacent to the side weirs is
effectively prevented from being lowered in temperature.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] [FIG. 1] A schematic diagram showing an example of a twin
roll caster.
[0021] [FIG. 2] A schematic diagram showing flow velocity
distribution on a free surface of molten metal adjacent to a molten
metal feed nozzle shown in FIG. 1.
[0022] [FIG. 3] A partial perspective view from below showing a
first embodiment of a molten metal feed nozzle according to the
invention.
[0023] [FIG. 4] A schematic diagram of the molten metal feed nozzle
in FIG. 3 looking axially of the chilled rolls.
[0024] [FIG. 5] A schematic diagram of the molten metal feed nozzle
in FIG. 3 looking tangentially of the chilled roil.
[0025] [FIG. 6] A schematic diagram showing flow velocity
distribution on a free surface of molten metal adjacent to the
molten metal feed nozzle of FIG. 3.
[0026] [FIG. 7] A partial perspective view from below showing a
second embodiment of a molten metal feed nozzle according to the
invention.
[0027] [FIG. 8] A schematic diagram of the molten metal feed nozzle
in FIG. 7 looking axially of the chilled rolls.
[0028] [FIG. 9] A partial perspective view from below showing a
third embodiment of a molten metal feed nozzle according to the
invention.
[0029] [FIG. 10] A schematic diagram of the molten metal feed
nozzle in FIG. 9 looking axially of the chilled rolls.
EXPLANATION OF THE REFERENCE NUMERALS
[0030] 2 side weir
[0031] 7 molten metal pool
[0032] 11,12,13 extension
[0033] A area
[0034] G nip or gap
[0035] P1 point
BEST MODE FOR CARRYING OUT THE INVENTION
[0036] Embodiments of the invention will be described in
conjunction with the drawings.
[0037] FIGS. 3 to 6 show a first embodiment of a molten metal feed
nozzle according to the invention in which parts identical with
those in FIGS. 1 and 2 are represented by the same reference
numerals.
[0038] Each of nozzle ends is provided with an extension 11 which
has a lower portion immersed in a molten metal pool 7 and extends
toward a side weir 2 such that a stagnation area A (see FIG. 2)
disappears on a free liquid surface of molten metal 4.
[0039] The extension 11 is in the form of a quadrangular pyramid
lying sidelong and is convergent to point P1 extremely close to the
side weir 2.
[0040] In the twin roll caster with such molten metal feed nozzle
incorporated, the stagnation area A on the free liquid surface of
the molten metal 4 is displaced by the extension 11 contiguous with
the nozzle end to suppress generation of an unwanted solidification
shell. As a result, no unwanted solidification shell is pinched as
foreign matter by the solidification shells generated on the outer
peripheries on the chilled rolls 1 for production of the strip 3,
whereby break of the strip 3 due to enlargement of the nip G
between the rolls can be averted.
[0041] In addition, the extension 11 is gradually reduced in volume
toward the side weir 2, so that heat transmission from the molten
metal 4 to the extension 11 is reduced. As a result, the molten
metal 4 adjacent to the side weir 2 can be effectively prevented
from being lowered in temperature and no unwanted solidification
shell for the side weir 2 is generated.
[0042] FIGS. 7 and 8 shows a second embodiment of a molten metal
feed nozzle according to the invention. In the figures, parts
identical with those shown in FIGS. 3 to 6 are represented by the
same reference numerals.
[0043] Each of nozzle ends is provided with an extension 12 which
has a lower portion immersed in a molten metal pool 7 and extends
toward a side weir 2 such that a stagnation area A (see FIG. 2)
disappears on a free liquid surface of molten metal 4.
[0044] The extension 12 is wedge shaped and is converged to a
horizontal line segment between points P2 and 23 extremely close to
the side weir 2.
[0045] In the twin roll caster with such molten metal feed nozzle
incorporated the stagnation area A on the free liquid surface of
the molten metal 4 is displaced by the extension 12 contiguous with
the nozzle end to suppress generation of unwanted solidification
shell. As a result, no unwanted solidification shell is pinched as
foreign matter by the solidification shells generated on the outer
peripheries of the chilled roll 1 for production of the strip 3,
whereby break of the strip 3 due to enlargement of the nip G
between the rolls can be averted.
[0046] In addition, the extension 12 is gradually reduced in volume
toward the side weir 2, so that heat transmission from the molten
metal 4 (see FIG. 6) to the extension 12 is reduced so that the
molten metal 4 adjacent to the side weir 2 can be effectively
prevented from being lowered in temperature and no unwanted
solidification shell for the side weir 2 is generated.
[0047] FIGS. 9 and 10 show a third embodiment of a molten metal
feed nozzle according to the invention. In the figures, parts
identical with those in FIGS. 3 to 7 are represented by the same
reference numerals.
[0048] Each of nozzle ends is provided with an extension 13 which
has a lower portion immersed in a molten metal pool 7 and extends
to a side weir 2 such that a stagnation area A (see FIG. 2)
disappears on a free liquid surface of molten metal 4.
[0049] The extension 13 is in the form of tapered quadratic prism
lying sidelong and is converged to vertical face with corners P2,
P3, P4 and P5 extremely close to the side weir 2.
[0050] In the twin roll caser with such molten metal feed nozzle
incorporated, the stagnation area A of the free liquid surface of
the molten metal 4 is displaced by the extension 13 contiguous with
the nozzle end to suppress generation of unwanted solidification
shell. As a result, no unwanted solidification shell is pinched as
foreign matter by the solidification shells generated on the outer
peripheries of the chilled roll 1 for production of the strip 3,
whereby break of the strip 3 derived from enlargement of the nip G
between the rolls can be averted.
[0051] Heat transmission from the molten metal 4 (see FIG. 6) to
the extension 13 may be much in comparison with the first and
second embodiments; however, the third embodiment is easier in
machining upon fabrication of the molten metal feed nozzle.
[0052] It is to be understood that a molten metal feed nozzle of
the invention is not limited to the above embodiments and that
various changes and modifications may be made without departing
from the scope of the invention.
INDUSTRIAL APPLICABILITY
[0053] A molten metal feed nozzle of the invention is applicable to
production of strips of steel or other various metals.
* * * * *