FR2694221A1 - Internal nozzle in refractory material for metallurgical vessels. - Google Patents

Abstract

The subject of the present invention is an internal pouring tube (nozzle) (10) made from refractory material for metallurgical vessels (1) for the bottom casting of metal, including a base wall (2, 3) intended to receive the said pouring tube (10) and being fitted (lined) with a nozzle seating block. This internal pouring tube (10) is formed from a vertical body (11) delimiting a runner (casting channel) (12) and equipped at its upper part with a shoulder (13) forming the nozzle seating block and the lower part (14) of which constitutes a reference plate under which bears a casting (pouring) tube (5) which is interchangeable during casting.

Description

The subject of the invention is an internal nozzle made of refractory material for

metallurgical vessels

from the bottom.

  The metallurgical vessels for downward casting, such as for example the continuous casting distributors, possibly closed with a stopper, have a bottom wall generally provided with a seat brick in which an internal nozzle is housed. This internal nozzle delimits a pouring channel through which the molten steel contained in the container flows continuously in an ingot mold

using a pouring tube.

  So far, the outer end of the

  internal nozzle is housed in a fixed reference plate

rence.

  The pouring tube has a top flange

  refractory material and is caused to slide under the action of a double pneumatic cylinder along the reference plate, so as to slide along it from a loading position to a service position or plugging in the axis of the container pouring channel and from the service position to a release position, so as to allow

  changing the pouring tube without lifting the container.

  The contact surfaces between, on the one hand, the pouring tube and the reference plate and, on the other hand, the lower end of the internal nozzle and this reference plate, constitute possible passages for the ambient air. or steel in the event of a leak. Indeed, these areas are subjected to a significant depression created in the pouring channel by

  the metal jet flowing in said channel.

  Until now, various solutions have been implemented to prevent the entry of air into the pouring channel between the contact surface of the pouring tube and the reference plate, by providing an annular belt at this surface. inert gas so as to isolate the molten metal from the ambient air by a continuous gaseous protection barrier which is however quite expensive due to consumption

significant gas.

  However, the problem of sealing at the level of the contact surface between the internal nozzle and the reference plate has not been effectively resolved. Furthermore, the internal nozzle has so far been introduced into the metallurgical container from below, which poses a problem for the maintenance of this nozzle. In fact, when the stopper rod is applied to the upper surface of the internal nozzle, the latter tends to become detached from the bottom of the metallurgical container, which can cause deterioration of the

  device for supplying and exchanging the poured tube.

  The present invention aims to remedy these drawbacks by proposing an internal nozzle whose design makes it possible to improve its retention in the bottom of the metallurgical container and to reduce the areas

  air infiltration into the sprue.

  The present invention therefore relates to an internal nozzle made of refractory material for metallurgical containers for casting metal from below, comprising a bottom wall intended to receive said nozzle and being lined with a seat brick, characterized in that it is formed by a vertical body delimiting a pouring channel and provided at its upper part with a shoulder forming at least part of the seat brick and the lower part of which constitutes a reference plate under which a pouring tube rests

  interchangeable during casting.

  According to other characteristics of the invention: the shoulder is frustoconical, the frustoconical shoulder is flared upward, the upper surface of the shoulder of the vertical body is inclined towards the pouring channel, the inlet of the pouring channel has a rounded inner edge, the vertical body comprises means for diffusing an inert gas in the pouring channel, the means for diffusing the inert gas are formed by a cylindrical ring of porous material arranged in a groove formed in the vertical body and the inner wall of which constitutes a length portion of said pouring channel, said groove communicating

  with at least one neutral gas supply.

  the means for diffusing the inert gas are formed by a cylindrical ring of dense material provided with vertical slots and disposed in a groove formed in the vertical body, the internal wall of said ring constituting a length portion of said pouring channel and said communicating groove with at least one arrival

inert gas.

  The invention will be better understood using

  the description which follows will be given only as a

  example with reference to the single appended drawing which represents a vertical section view of a nozzle

  internal according to the invention, placed in a container

pient metallurgical.

  In Figure 1, there is shown a portion of the bottom of a metallurgical vessel for casting from below

  designated as a whole by the reference 1.

  The bottom wall 2 is covered with a

  internal coating 3 of refractory material.

  The bottom of the metallurgical container 1 has a tap hole 4 in which a nozzle is placed

  internal 10 of refractory material.

  The internal nozzle 10 is formed by a vertical body 11 delimiting a flow channel 12 of the steel

  liquid in container 1.

  This vertical body 11 is provided at its upper part with a shoulder 13 forming the seat brick which is usually built in the refractory lining 3 and in which the nozzle is housed.

internal.

  The lower part 14 of this vertical body l 1 constitutes a reference plate under which is supported a pouring tube 5 of the molten metal in a

  casting mold not shown.

  The internal nozzle 10 comprising the shoulder 13 and the lower part 14 constitutes a monolithic assembly.

  The shoulder 13 is frustoconical, preferably

  rence flared upwards, i.e. inwards

of the metallurgical vessel 1.

  The upper surface 15 of the shoulder 13 is inclined towards the runner 12 and the inlet of said runner 12 has a rounded inner edge 16

  which forms a seat for a distaff not shown.

  On the other hand, the vertical body II of the internal nozzle 10 comprises means for diffusing an inert gas, such as for example argon, into the pouring channel 12 to carry out the bubbling of argon along

  the inner wall of said runner.

  These means for diffusing the inert gas are formed by a cylindrical ring 17 made of porous material arranged in a groove 18 formed in the vertical body 11 The internal wall of the cylindrical ring 17 constitutes a length portion of the pouring channel 12 and the groove 18 is connected to at least one inlet 19 of the inert gas.

  Due to the porosity of the material

  killing ring 17, the inert gas passes through said ring

  and enters the runner 12.

  The means for diffusing the inert gas can also be constituted by a ring or a toroid in

porous material.

  The pouring tube 5 is supported by a supply and exchange device for said tube and designated

  as a whole by reference 20.

  According to a variant, the means for diffusing the inert gas may consist of a cylindrical ring of dense material provided with vertical slots and arranged in the groove 18 formed in the vertical body 11 The internal wall of this ring also constitutes a length portion of the flow channel 11 and the groove 18 communicates with at least one inlet 11

inert gas.

  The pouring tube 5 is applied elastic-

  ment using guides 6 against the lower part 14 of the internal nozzle 10 which constitutes a reference plate. The internal nozzle 10 is inserted into the

  metallurgical container 1 from above.

  The monolithic construction of the nozzle

  internal 10 has many advantages.

  The reference plate formed by the lower part of the nozzle serves as an upper plate for the

  device for supplying and exchanging the pouring tube.

  This construction makes it possible to improve

  rer the solidity of the vertical body of the internal nozzle

  so that this nozzle is more resistant to stresses

  thermal and mechanical shock, especially during

the application of the distaff.

  On the other hand, during the application of the stopper rod, the internal nozzle tends to get caught in the refractory lining of the metallurgical container due to the frustoconical shape flared upwards.

  shoulder 13 which prevents deterioration of the device

  tif of supply and exchange of the pouring tube.

  Finally, the nozzle according to the present invention makes it possible to limit the number of joints and possible passages for the ambient air and the molten metal as much as possible. Thus, the cleanliness of the metal and the reliability of the system are improved and the random wear of the

  refractory pieces are decreased.

Claims (7)

  1 internal nozzle made of refractory material for metallurgical vessels (1) poured from below, comprising a bottom wall (2) intended to receive said nozzle (10) and being furnished with a seat brick, characterized in that it is formed by a vertical body (11) delimiting a pouring channel (12) and provided at its upper part with a shoulder (13) forming the seat brick and whose lower part (14) constitutes a reference plate under which relies   an interchangeable pouring tube (5) during casting.   2 internal nozzle according to claim 1,   characterized in that the shoulder (13) is frustoconical.   3 internal nozzle according to claim 1, characterized in that the frustoconical shoulder (13) is flared up.   4 internal nozzle according to claim 1, characterized in that the upper surface (15) of the shoulder (13) of the vertical body (11) is inclined towards the pouring channel (12).   Internal nozzle according to claim 1, characterized in that the inlet of the pouring channel (12)   has a rounded inner edge (16).   6 internal nozzle according to claim 1, characterized in that the vertical body (11) comprises means (17, 18) for diffusing an inert gas in the pouring channel (12).   7 internal nozzle according to claim 6, characterized in that the means for diffusing the inert gas are formed by a cylindrical ring (17) of porous material disposed in a groove (18) formed in the vertical body (11) and whose wall internal constitutes a length portion of said pouring channel (12), said groove (18) communicating with at least one inlet (19) inert gas.   8 internal nozzle according to claim 6, characterized in that the means for diffusing the inert gas are formed by a cylindrical ring of dense material provided with vertical slots and disposed in a groove (18) formed in the vertical body (11), the inner wall of said ring constituting a length portion of said pouring channel (12) and said groove (18) communicating with at least one inlet (19) of the inert gas.