KR20050113171A - 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 - Google Patents

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.

Description

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}

The present invention relates to a fireproof plate for a device for insertion and / or removal of nozzles for casting equipment in combination with a sliding plate flow-control device.

Casting of the melt is generally carried out by means of a facility having several refractory elements forming a casting channel between two successive metallic containers. These refractory elements perform the function of conveying the melt, protecting the melt against chemical attack and cooling of the ambient atmosphere, and optionally controlling the melt casting flow. Thus, in continuous casting, the melt contained in the casting ladle is injected through the discharge orifice, which is elongated by a nozzle disposed at the bottom of the ladle and extending through the bottom wall. Under the bottom wall there is a device for the flow control of the liquid metal stream, which consists of a refractory plate, each provided with a casting orifice, which can be aligned or moved relative to each other by the relative displacement of the plates. It deforms the cross sectional flow area formed by the superposition of the injection orifices. The melt flows from the flow control device to the nozzle and is generally referred to as a collector nozzle of small length. Often, a shroud casting tube is provided that is adapted to cover the stream exiting the collector nozzle during the progress to the bin. Typically, this shroud is installed at the downstream end of the collector nozzle. However, from US Pat. No. 5,695,674, a casting installation is also known which forms an assembly in which the collector nozzle and shroud nozzle are introduced into the casting position by sliding into the guide rail. International patent application WO-A1-9920420 discloses such a shrouding tube.

Thereafter, the metal injected into the bin through the shroud tube is directed towards one or more injection orifices disposed at the bottom of the bin. This orifice is extended by a nozzle that can extend directly into the ingot-mould. In this case, the flow-control of the melt injected from the bin is performed by a stopper system capable of closing the injection orifice arranged in the bottom wall. As a variant, the nozzle comprises a plurality of adjacent elements, in particular an internal nozzle terminating upstream of an injection orifice disposed in the bottom wall and terminating downstream of an end formed as a flat surface, and of a flat surface which coincides with the flat surface of the inner nozzle. It may be formed as a subentry nozzle terminating upstream. Such equipment can replace the subentry nozzle with a suitable device (as disclosed in patent EP-A1-192,019) without disturbing casting. Even in this case, flow-control of the melt injected from the vat is performed by a stopper system capable of closing the injection orifice arranged on the bottom wall. Other variants are also known in which a flow-control device with a plate operating according to the same principle as the flow-control device described above in connection with the casting ladle is inserted between the inner nozzle and the sub-entry nozzle. Patent EP-B1-441,927 discloses a facility of this type.

1 and 1a show a plan view of two different fire resistant plates according to the invention,

2 and 2a show cross-sectional views taken along line A-A of FIGS. 1 and 1 a, respectively,

3 shows a cross-sectional view taken along B-B of FIG. 1,

4 and 4A are perspective views seen from the bottom of the plate of FIGS. 1 and 1A, respectively.

More specifically, the invention relates to a plant comprising a device for insertion and / or removal of a nozzle for a casting plant in combination with a sliding plate flow-control device.

The possibility of inserting and / or replacing nozzles during casting without disturbing casting has been described above. Injection nozzles intended to guide the melt from a metal container towards another container are actually wear parts that are subjected to mechanical, chemical, and thermally strong stresses to the extent that their lifetime can limit the casting time. In this regard, there are many problems to be solved by the plates according to the invention.

Indeed, the lower plate of the sliding plate flow-control device is also a stationary plate of the device for insertion and / or removal of a nozzle for a casting plant in combination with the sliding plate flow-control device, wherein for the flow control device the nozzle The device for insertion and / or removal is directed from the insertion position to the casting position. These two functions impose the following requirements that are almost inconsistent.

The bottom plate of the sliding flow-control device should at most be placed in a housing supporting the plate to provide a complete seal between the upper surface of the plate and the mating surface of the movable plate of the flow-control device.

The lower surface of the plate should be able to guide the nozzle during the displacement from the introduction position towards the casting position.

If the plate is not sufficiently supported into its housing, the plate is not actually uniformly supported. In particular, pressure may not occur evenly around the plate's injection orifice, and what may be called "pinning" resulting from the formation of thin strips or solidified metal between the stationary plate and the movable plate. If this happens repeatedly, the solidified metal strip acts as a wedge, pushing the two plates away. This can be done by the penetration of molten metal which leads to an immediate termination of the casting operation.

If the guide surface cannot guide the nozzle from the introduction position to the casting position sufficiently accurately, there is a fear that this casting nozzle will be in an incorrect position due to conceivable negative results.

In addition, for economic reasons, it is important for the fire resistant plate to have as small dimensions as possible, especially in terms of thickness. However, the casting channel extending through the bottom plate of the sliding plate flow-control device is very severely corroded due to turbulence and the asymmetric molten metal stream passing through the turbulence. In particular, it is important to prevent such dislodged metal streams from impacting the walls of the casting channel in the vicinity of the discharge orifice, otherwise formed by contact with adjacent fire resistant elements around the orifices of the casting channel. The risk of damage to the seal can be increased.

Accordingly, the inventors of the present application have sought to solve these problems, and have come to the concept of providing protrusions on the plates. Even so, the shape of the plate should still be optimal to solve the above-mentioned problems.

In order to facilitate easy understanding of the present invention, the present invention will now be described based on the exemplary drawings. However, these drawings do not limit the invention in any way.

According to the invention, a fireproof plate for a device for insertion and / or removal of a nozzle for a casting plant in combination with a sliding plate flow-control device is

a) an orifice 2 is provided which forms an inlet of the casting channel 3 through the sliding plate, the sealing surface being at least around the orifice 2 together with the face conforming to the face of the movable plate of the flow-control device; A first surface 1 capable of forming

b) a second surface 4 arranged to lie within the housing of the device, the second surface 4 being provided with a planar protrusion 5 enclosing the casting channel 3 and extending through the bottom wall of the housing,

c) a third surface 6 formed by the flat surface of the planar protrusion 5 provided with an orifice 7 which forms an outlet of the casting channel 3 through the sliding plate. The third surface 6 is essentially

Forming a sealing surface at least around the orifice 7 together with the matching face of the refractory tube in the casting position,

Act as a guide surface for guiding the refractory tube from the introduction position to the casting position, the shape of the third surface being in contact with the mating surface of the fire tube as the fire tube proceeds from the introduction position to the casting position. The portion of the third surface 6 is adapted to increase.

With such a fireproof plate, at best the requirement for supporting the bottom of the plate is maximized while maximizing the bottom surface that can be used to guide the tube from the introduction position to the casting position.

The preferred shape of the protrusion is a tip shape, which tip 8 is directed towards the introduction position of the fire tube. From now on, the initial effort required to move the tube from the introduction position is very small and gradually increases as the tube moves closer to the casting position. If the tubes are not completely aligned in the insertion and / or separation device of the nozzle, the tube can be adjusted by this particular shape.

Oval, triangular or oval is a particularly suitable shape. Egg shapes which can prevent sharp angles (see FIGS. 1, 1A, 4 and 4A) and which can maximize the above-mentioned effect are particularly preferred.

If a chamfer is provided at the end of the tip 8, this advantageous effect is further enhanced.

Alternatively, it is also possible to have a chamfer at the opposite end of the tip 8. This is particularly advantageous when it is necessary to move another tube or any other refractory element which must be introduced from a direction opposite the tube introduction direction to the casting position or any other suitable position. For example, it may be a collector nozzle that stays in a standby position on the other side of the device.

The plate according to the present invention may or may not include a metal envelope.

The molten metal stream can be contaminated by passing through a seal around the inlet orifice 2 between the surface 1 and the bottom of the sliding plate flow-control device or around the outlet orifice 7 between the top and surface 6 of the tube. Where it is advantageous to protect the metal stream from the surrounding ambient environment, it may also be possible to provide means which can form an inert gas shroud channel that surrounds the orifice to be protected. For example, as shown in FIGS. 1 to 4, an inert gas line 9 can be provided which is connected to the circular groove 10 surrounding the outlet orifice 7 at the third surface 3. Any other type of similar groove can be provided around the orifice 2.

Ultimately, according to another advantageous variant of the invention, the second passage 12 extends from the orifice 11 of the third surface 6 toward the orifice 13 of the first surface 1 through the plate. Is provided. Preferably, this second passage 12 has a smaller dimension than the casting channel 3 and will be localized away from the casting channel 3, for example adjacent to the end of the tip 8. This embodiment is illustrated in Figures 1A, 2A and 4A.

If opening the flow-control device alone does not allow for natural initiation of the casting procedure, the second passage may overlap the casting channel of the movable plate and remove any obstruction from the casting channel, for example by oxygen lancing. A lancing device can be introduced through the orifice and passage 12 of the downstream refractory element. In this case, it may be useful to arrange the collector nozzle 11 under a orifice 11 or in a refractory plate with means for providing access to the casting channel through the refractory plate.

Claims (10)

a) an orifice 2 is provided which forms an inlet of the casting channel 3 through the sliding plate, the sealing surface being at least around the orifice 2 together with the face conforming to the face of the movable plate of the flow-control device; A first surface 1 capable of forming b) a second surface 4 arranged to lie within the housing of the device, the second surface 4 being provided with a planar protrusion 5 enclosing the casting channel 3 and extending through the bottom wall of the housing, c) a third surface 6 formed by the flat surface of the planar protrusion 5 provided with an orifice 7 which forms an outlet of the casting channel 3 through the sliding plate. A fireproof plate for a device for insertion and / or removal of a nozzle for a casting machine in combination with a sliding plate flow-control device comprising: The third surface 6 is Forming a sealing surface at least around the orifice 7 together with the matching face of the refractory tube in the casting position, Act as a guide surface for guiding the refractory tube from the introduction position to the casting position, The shape of the third surface is such that the portion of the third surface (6) of the plate in contact with the mating surface of the fire tube is increased as the fire tube advances from the introduction position to the casting position. 2. The fire resistant plate according to claim 1, wherein the third surface (6) has the shape of a tip, the tip (8) being directed towards the introduction position of the fire tube. 3. A fire resistant plate according to claim 2, wherein the third surface (6) has a chamfer formed at the end of the tip (8). 3. The fire resistant plate according to claim 2, wherein the third surface (6) has a chamfer formed on the side opposite to the end of the tip (8). A fire resistant plate according to claim 1, wherein the third surface (6) is elliptical in shape. A fire resistant plate according to claim 1, wherein the third surface (6) is triangular in shape. The fire resistant plate according to claim 1, wherein the third surface (6) is egg shaped. The fireproof plate of Claim 1 provided with inert gas supply means. 9. The fire resistant plate according to claim 8, wherein said inert gas supply means comprises a gas conveying line (9) and a circular groove (10) surrounding the outlet orifice (7) of the casting channel at the third surface (6). 3. Fire resistant plate according to claim 2, wherein the third surface (6) comprises a second orifice (11) adjacent the end of the tip (2).