LU85196A1 - IMPROVEMENTS IN METALLURGICAL CONTAINERS, ESPECIALLY TEMPERATURE HOLDING POCKETS - Google Patents

Description

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METALLURGICAL RESEARCH CENTER -CENTRUM V00R RESEARCH IN DE METALLURGIE,

Non-profit association -Vereniging zonder winstoogmerk in BRUXELLES, (Belgium).

Improvements to metallurgical vessels, in particular to temperature maintenance bags.

The present invention relates to an improvement in metallurgical vessels, and more particularly in bags intended to maintain a metal or a metal alloy in the liquid state. It applies in particular to foundry pockets.

There is already known, in particular from Belgian patent No. 843.324 by the same applicant, a pocket of the type mentioned above, provided with an insulating cover and the refractory lining of which includes a heating part. This heating part is preferably made up of a layer of pulverulent graphite formed in the thickness of the refractory lining and supplied with electric current by electrodes generally made of graphite.

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Such pockets remarkably ensure the maintenance of the temperature of the molten metal which they contain and they give in this respect all satisfaction, in particular when the quantities of metal are small and therefore liable to cool more quickly.

There is, however, a problem when casting molten metal, for example in molds.

The Applicant has in fact found that the usual casting systems such as the pouring bricks with stopper and buffer, or the sliding shutters, could not * ensure, with certainty, sufficient sealing against the molten metal, between the different layers of the lining of the pocket bottom. There is therefore a significant risk of infiltration of liquid metal from the pouring orifice to the heating part of the lining with, as a consequence, the possibility of short circuits between the electrodes.

To remedy this drawback, the applicant has developed a particular casting device which is not subjected to the ferrostatic pressure exerted by the molten metal and which provides increased tightness during casting.

It will be recalled that the pockets in question here are provided with an insulating cover and pressure pieces formed by circular crown segments. The inside and outside diameters of this crown correspond to the inside and outside diameters of the layer of powdered graphite formed in the thickness of the lining. When the cover is put in place and tightened on the pocket, it rests on the crown segments which, in turn, exert on the graphite powder a high pressure intended to ensure and maintain its compactness.

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The present invention relates to a pouring device specially suitable for emptying temperature holding bags of the type which has just been mentioned.

The metallurgical receptacle, in particular the holding and / or pouring ladle which is the subject of the present invention, comprising on the one hand an inner refractory lining in several layers, one of these layers consisting of powdered graphite, and comprising on the other hand an insulating cover which, by means of pressure pieces of suitable shape, in particular of crown segments, exerts pressure on said layer of powdered graphite, is essentially characterized in that it has, in its side wall, an orifice situated at a level higher than the maximum level reached by the molten metal, and in that it comprises a pouring tube fitting in leaktight manner at one of its ends to the said orifice formed in the wall side of the container, the said tube passing through the side wall and / or the container cover, through a suitable conduit.

According to an advantageous embodiment of the device of the invention, said pouring tube passing through the side wall of the container passes through an opening formed in one of said pressure pieces.

Also according to the invention, the opening made in the pressure piece and / or the conduit formed in the cover for the passage of the pouring tube, has a cross section of elongated shape in the vertical direction when the container is in the position of maintenance.

It is also advantageous, according to the invention, to shape said orifice so that the longitudinal axis of said pouring tube is inclined relative to the horizontal, when-, fiy / * * - 4 - that the container is in the holding position.

Still according to the invention, it is advantageous to use a pouring tube made of a material resistant to thermal shock and therefore not requiring preheating before its installation, such as silica glass.

When the metal is a steel with a high manganese content, it is also advantageous, according to the invention, to use a tube made of a material consisting either of alumina and from 5 to 40%, preferably from 15 to 30% of graphite, or zirconium oxide and from 5 to 40%, preferably from 15 to 30% of graphite.

In the case of the alumina-based material, part of the graphite, for example between a quarter and a half of the graphite, can be replaced by boron nitride.

By way of example intended only to illustrate a device according to the invention, the attached figure schematically represents a holding bag equipped with a pouring tube passing through the side wall and the cover of the bag.

Figure la shows a holding pocket 1 provided with a refractory lining in several layers, in which is formed a heating part 2 made of powdered graphite. A cover 3 is fixed to the pocket 1 by means of a tightening system shown diagrammatically at 4. This cover 3 exerts pressure on the graphite layer 2 by means of pressure pieces 5. The pouring tube 6 is adapted by one end in an orifice 7 formed in the side wall of the pocket, above the level of the metal bath 8. In the embodiment which is shown here, the pouring tube 6 passes through the pressure piece 5 through an opening 9 of elongated section.

The part of the conduit 10 formed through the cover also has an elongated section, intended to allow tightening of the cover 3 in order to compress the powdered graphite.

FIG. 1b illustrates a possible form of a pressure piece 5 pierced with an elongated opening 9.

The molten metal contained in a container according to the invention is poured by simply tilting the container. In the temperature maintenance position, the pouring orifice is closed by a plug and it does not undergo any ferrostatic pressure from the bath. There is therefore no risk of metal infiltration. In the pouring position, does the pouring tube fitted tightly to the pouring hole allow the metal to flow without the slightest possibility of contact between the metal and the graphite? also in this position, the ferrostatic pressure exerted on the pouring orifice is low compared to that which a pouring orifice formed in the bottom of the container would undergo.

It is also possible, thanks to the pouring tube fitted to the containers according to the invention, to improve the precision of the casting, both with regard to the quantity of metal cast and with regard to the positioning of the end. outlet-from the pouring tube.

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Claims (8)

1. Metallurgical container, in particular pocket for maintaining the temperature of molten metal, comprising on the one hand an inner refractory lining in several layers, one of these layers consisting of powdered graphite, and comprising on the other hand an insulating cover which , by means of pressure pieces of appropriate shape, in particular in the form of crown segments, exerts pressure on said layer of powdered graphite, characterized in that it has, in its side wall, an orifice located at a level higher than the maximum level reached by the molten metal, and in that it comprises a pouring tube fitting in a sealed manner by one of its ends to the said orifice made in the side wall of the container, the said tube pouring through the side wall and / or the cover of said container by a suitable -conduit. 2. Metallurgical container according to claim 1, characterized in that said pouring tube passing through the side wall of the container passes through an opening in one of said pressure pieces. 3. Metallurgical container according to either of claims 1 and 2, characterized in that said opening made in the pressure piece and / or the conduit formed in the cover have a cross section of elongated shape in the direction vertical when the container is in the holding position. 4. Metallurgical container according to either of Claims 1 to 3, characterized in that the said orifice made in the side wall of the container is shaped in such a way that the axis longitudinal of said pouring tube is inclined relative to the horizontal when the container is in the holding position. 5. Metallurgical container according to either of claims 1 to 4, characterized in that the pouring tube is made of a material having a high resistance to thermal shock, for example made of silica glass. 6. Metallurgical container according to either of claims 1 to 4, characterized in that the pouring tube is made of an alumina-based material and containing from 5 to 40%, and preferably from 15 at 30% by weight of graphite. 7. Metallurgical container according to claim 6, characterized in that in the material of the pouring tube, ^ a portion of the graphite, preferably between a quarter and a half of the graphite, is replaced by boron nitride. 8. Metallurgical container according to either of claims 1 to 4, characterized in that the pouring tube is made of a material based on zirconium oxide and containing from 5 to 40%, and preferably from 15 to 30% graphite. Drawings: plates ~ ciont — A cover page ....... description psgss &. pcgos ds demande,, ------ description Luxembourg, i2 .fi FEV m Le mandqjtyré: / Me. /// J ^ i I] fj f \ f ff /// 6 ^ L. J îinl'tU i / 7 J / Λ