U.S. patent application number 10/538187 was filed with the patent office on 2006-06-08 for refractory plate for a device for the insertion and/or removal of a nozzle for a casting installation combined with a sliding plate flow-control device.
Invention is credited to Vincent Boisdequin, Mariano Collura.
Application Number | 20060118268 10/538187 |
Document ID | / |
Family ID | 32479870 |
Filed Date | 2006-06-08 |
United States Patent
Application |
20060118268 |
Kind Code |
A1 |
Collura; Mariano ; et
al. |
June 8, 2006 |
Refractory plate for a device for the insertion and/or removal of a
nozzle for a casting installation combined with a sliding plate
flow-control device
Abstract
The invention relates to a refractory plate for a device for the
insertion and/or removal of a nozzle for a casting installation
combined with a sliding plate flow-control device comprising a) a
first surface (1) provided with an orifice (2) defining the entry
of a casting channel (3) through the plate and able to form a
sealing surface, at least around the orifice (2), with a face
matching the face of a mobile plate of the flow-control device; b)
a second surface (4) adapted to rest in housing of the device and
provided with a plane protuberance (5) circumscribing the casting
channel (3) and extending through the bottom wall of the housing,
and c) a third surface (6) defined by the plane surface of the
protuberance (5) provided with an orifice (7), with a matching face
of a refractory tube in casting position, and to act as guiding
surface for the refractory tube from an introduction position to a
casting position, and being shaped so that the portion of the third
surface (6) in contact with the matching surface of the refractory
tube increases as the tube progresses from the introduction
position to the casting position. With this plate, an optimal
compromise between the necessity to support at most the lower part
of the plate while maximizing the lower surface available for
guiding the tube from its introduction position to the casting
position.
Inventors: |
Collura; Mariano;
(Strepy-Bracquegnies, BE) ; Boisdequin; Vincent;
(Naast, BE) |
Correspondence
Address: |
Robert S. Klemz, Jr.;Vesuvius USA
27 Noblestown Road
Carnegie
PA
15106-1632
US
|
Family ID: |
32479870 |
Appl. No.: |
10/538187 |
Filed: |
December 8, 2003 |
PCT Filed: |
December 8, 2003 |
PCT NO: |
PCT/BE03/00211 |
371 Date: |
June 9, 2005 |
Current U.S.
Class: |
164/437 ;
266/233; 266/266 |
Current CPC
Class: |
B22D 41/28 20130101;
B22D 41/42 20130101; B22D 41/56 20130101 |
Class at
Publication: |
164/437 ;
266/233; 266/266 |
International
Class: |
B22D 11/10 20060101
B22D011/10 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 10, 2002 |
EP |
02447251.6 |
Claims
1-9. (canceled)
10. Refractory plate for a device for the insertion and/or removal
of a nozzle for a casting installation combined with a sliding
plate flow-control device comprising a) a first surface provided
with an orifice defining the entry of a casting channel through the
plate and able to form a sealing surface, at least around the
orifice, with a face matching the face of a sliding plate of the
flow-control device; b) a second surface adapted to rest in housing
of the device and provided with a plane protuberance circumscribing
the casting channel and extending through the bottom wall of the
housing, and c) a tip-shaped third surface defined by the plane
surface of the protuberance provided with an orifice defining the
exit of the casting channel through the plate, the surface being
adapted (i) to form a sealing surface, at least around the orifice,
with a matching face of a refractory nozzle in casting position,
and (ii) to act as guiding surface for the refractory nozzle from
an introduction position to a casting position, the tip being
directed towards the introduction position of the refractory
nozzle.
11. Refractory plate according to claim 10, wherein the third
surface is provided with a chamfer at the end of the tip.
12. Refractory plate according to claim 10, wherein the third
surface is provided with a chamfer on the side opposite to the end
of the tip.
13. Refractory plate according to claim 10, wherein the third
surface is oval-shaped.
14. Refractory plate according to claim 10, wherein the third
surface is triangle shaped.
15. Refractory plate according to claim 10, wherein the third
surface is egg-shaped.
16. Refractory plate according to claim 10, wherein it is provided
with inert gas supplying means.
17. Refractory plate according to claim 16, wherein the inert gas
supplying means comprises a gas feeding line and a circular groove
circumscribing the exit orifice of the casting channel in the third
surface.
18. Refractory plate according to claim 10, wherein the third
surface is provided with a second orifice close to the end of the
tip.
Description
[0001] The present invention relates to a refractory plate for a
device for the insertion and/or removal of a nozzle for a casting
installation combined with a sliding plate flow-control device.
[0002] The casting of a melt is generally carried out with an
installation comprising several refractory elements forming a
casting channel between two consecutive metallurgical containers.
These elements fulfill different functions which are the transfer
of the melt, the protection of the melt against cooling and the
chemical attacks of the surrounding atmosphere and, optionally, the
control of the melt casting flow. Thus, in the continuous casting,
the melt contained in a casting ladle is poured through a discharge
orifice arranged in the bottom wall of the ladle and prolonged by a
nozzle extending through the bottom wall. Under the bottom wall,
there is generally a device for the flow-control of the liquid
metal stream, the device being constituted from refractory plates
provided each with a casting orifice which can be aligned or
shifted one with respect to the other by the relative displacement
of the plates so as to modify the cross-sectional flow area defined
by the superposition of the pouring orifices. The melt exits from
the flow-control device into a nozzle, having generally a small
length and called collector nozzle. The most often, a casting tube
intended for shrouding the stream discharged from the collector
nozzle during its way to a tundish is provided. Conventionally,
this shroud is fitted on the downstream end of the collector
nozzle. From the U.S. Pat. No. 5,695,674, a casting installation
wherein the collector nozzle and the shrouding nozzle form an
assembly introduced into the casting position by sliding into
guide-rails is however also known. The International patent
application WO-A1-9920420 discloses such a shrouding tube.
[0003] The metal poured through the shrouding tube into the tundish
is then directed towards one or more pouring orifices arranged in
the bottom wall of the tundish. This orifice is prolonged by a
nozzle which can run directly into the ingot-mold. In this case,
the flow-control of the melt poured from the tundish is performed
with a stopper system which can close the pouring orifice arranged
in the bottom wall. In a variant, the nozzle can be formed of
several adjacent elements, in particular, an inner nozzle ending
upstreamly with the pouring orifice arranged in the bottom wall and
downstreamly with an end formed as a plane surface and a subentry
nozzle ending upstreamly with a plane surface matching the plane
surface of the inner nozzle. Such an installation allows the
replacement with an appropriate device (such as described for
example in the patent EP-A1-192,019) of the subentry nozzle without
having to interrupt the casting. In this case also, the
flow-control of the melt poured from the tundish Is performed with
a stopper system which can close the pouring orifice arranged in
the bottom wall. Another variant wherein a flow-control device with
plates working according to the same principle as the flow-control
device above described in the context of the casting ladle is
inserted between the inner nozzle and the subentry nozzle is also
known. The patent EP-B1-441,927 discloses such a kind of
installation.
[0004] The present invention relates more particularly to an
installation comprising a device for the insertion and/or removal
of a nozzle for a casting Installation combined with a sliding
plate flow-control device.
[0005] The possibility to insert and/or to exchange a nozzle during
the casting without having to interrupt it has been mentioned
hereabove. The pouring nozzle intended to lead the melt from a
metallurgical container towards another one are indeed wear parts
which are strongly mechanically, chemically and thermally stressed
to an extent that their service life can limit the casting time. In
this context, there are many problems that the invention propose to
solve with the plate according to the present invention.
[0006] Indeed, the lower plate of the sliding plates flow-control
device is also the stationary plate of the device for the insertion
and/or removal of a nozzle for a casting installation combined with
a sliding plate flow-control device against which the nozzle is
brought from an insertion position towards a casting position by
the device for the insertion and/or removal. These two functions
impose hardly reconcilable requirements: [0007] the lower plate of
the sliding flow-control device must rest in a housing supporting
it at most so as to provide a perfect seal between its upper face
and the matching surface of the mobile plate of the flow-control
device, but, at the same time, [0008] its lower face must permit to
guide the nozzle during its displacement from the introduction
position towards its casting position.
[0009] If the plate is not enough supported into its housing, the
plate is indeed not homogeneously supported. In particular, the
pressure is not uniformly distributed around the pouring orifice of
the plate and an incident called "finning" consisting in the
formation of a thin strip of frozen metal between the stationary
plate and the mobile plate, can take place. If this incident occurs
repeatedly, the frozen metal strip acts as a wedge and push apart
the two plates. It can even end with an infiltration of molten
metal which cause the immediate termination of the casting
operations.
[0010] If the guiding surface is not sufficient to permit a correct
guiding of the nozzle from the introduction position towards the
casting position, the risk to have this casting nozzle in an
incorrect position is important with all the adverse consequences
that one can imagine.
[0011] Moreover, for economical reasons, it is important that the
refractory plates have as low as possible dimensions, in, in
particular as to its thickness. However, the casting channel
extending through the lower pate of the sliding plate flow-control
device is subjected to a very strong erosion due to the turbulent
and asymmetrical molten metal stream passing through it. In
particular, it is essential to prevent the metal stream so deviated
(unbalanced) to hit the casting channel wall in the vicinity of its
exit orifice, otherwise, the risk to damage the seal formed by the
contact with the adjacent refractory element around the orifice of
the casting channel would be great.
[0012] The inventors have thus seek to solve these problems and
have come to the idea of providing the plate in question with a
protuberance. Even so, its shape still had to be optimized so as to
solve the above mentioned problems.
[0013] In order to permit a better understanding of the invention,
it will now be described on the basis of the illustrative figures,
which however do not limit it in any way. On these figures, top
views of two different refractory plates according to the invention
have been depicted on FIGS. 1 and 1a. FIGS. 2 and 2a show to
cross-sectional views according to the line A-A respectively of
FIGS. 1 and 1a. FIG. 3 shows a cross-sectional view according to
the line B-B of FIG. 1. FIGS. 4 and 4a show perspective views from
the lower face of the plates respectively of FIGS. 1 and 1a.
[0014] According to the invention, the refractory plate for a
device for the insertion and/or removal of a nozzle for a casting
installation combined with a sliding plate flow-control device
comprises the following elements: [0015] a) a first surface (1)
provided with an orifice (2) defining the entry of a casting
channel (3) through the plate and able to form a sealing surface,
at least around the orifice (2), with a face matching the face of a
mobile plate of the flow-control device; [0016] b) a second surface
(4) adapted to rest in housing of the device and provided with a
plane protuberance (5) circumscribing the casting channel (3) and
extending through the bottom wall of the housing, and [0017] c) a
third surface (6) defined by the plane surface of the protuberance
(5) provided with an orifice (7) defining the exit of the casting
channel (3) through the plate. It is essential that the surface (6)
be adapted [0018] to form a sealing surface, at least around the
orifice (7), with a matching face of a refractory nozzle in casting
position, and [0019] to act as guiding surface for the refractory
tube from an introduction position to a casting position, and being
shaped so that the portion of the third surface (6) of the plate in
contact with the matching surface of the refractory tube increases
as the tube progresses from the introduction position to the
casting position.
[0020] With this plate, an optimal compromise between the necessity
to support at most the lower part of the plate while maximizing the
lower surface available for guiding the tube from its introduction
position to the casting position.
[0021] The preferred shape for the protuberance is a tip shape, the
tip (8) being directed towards the introduction position of the
refractory tube. Henceforth, the initial efforts required to move
the tube from its introduction position are quite low and increase
progressively as the tube moves closer to its casting position. In
case the tube is not perfectly aligned in the nozzle insertion
and/or removal device, this particular shape allows an adjustment
of the tube during its progression in the device.
[0022] Particularly suitable shape are the oval, triangle, or egg
shapes. The egg shape (see on the FIGS. 1, 1a, 4 and 4a) permitting
to avoid sharp angles and maximizing the above described effect is
particularly preferred.
[0023] The presence of a chamfer at the end of the tip (8)
strengthen even more this advantageous effect.
[0024] Alternatively, it Is also possible to have a chamfer on the
opposite end of the tip (8). This is particularly advantageous when
it is necessary to bring to the casting position, or to any other
appropriate position, another tube or any other refractory element
which has to be Introduced from a direction opposite to the tube
introduction direction. For example, this can be a collector nozzle
which would be parked in a waiting position on the other side of
the device.
[0025] The plate according to the invention can or not be provided
with a metallic envelope.
[0026] If it is desired to protect the metal stream from the
ambient atmosphere likely to contaminate the molten metal stream by
passing through the seal either around the entry orifice (2)
between the surface (1) and the lower surface of the sliding plate
flow-control device or around the exit orifice (7) of the surface
(6) and the upper surface of the tube, it is also possible to
provide means permitting the formation of an inert gas shrouding
channel circumscribing the orifice to protect. For example, one can
have an inert gas line (9) feeding a circular groove (10)
circumscribing the exit orifice (7) in the third surface (6) as
depicted on the FIGS. 1 to 4. A groove similar of or any other kind
can be present around the orifice (2).
[0027] Eventually, according to another advantageous variant of the
invention, a second passage (12) extending through the plate from
an orifice (11) of the third surface (6) towards an orifice (13) of
the first surface (1) is provided. Preferably, this second passage
(12) will have smaller dimension than the casting channel (3) and
will be localized far from the casting channel (3), for example
close to the end of the tip (8). This embodiment is depicted on
FIGS. 1a, 2a and 4a.
[0028] In case it is not possible to start naturally the casting
sequence, just by opening the flow-control device, it is then
possible to bring this second passage in register with the casting
channel of the mobile plate and to introduce, through the passage
(12) and the orifices of the downstream refractory elements a
lancing device which will allow, for example by oxygen lancing to
free the casting channel from any obstruction. In this case, it can
be useful to position a collector nozzle (11) under the orifice
(11) or to have a refractory provided with means allowing the
access to the casting channel passing through the refractory
plates.
* * * * *