LU87443A1 - DEVICE FOR CASTING A METAL IN A CONTINUOUS CASTING LINGOTIERE - Google Patents

Description

Λ * 7 Λ jk IX GRAND-D UCHÉ DE LUXEMBOURG

Patent Ν ° .8BL 4210

Minister of Justice. AT? §? ... Economy and the Middle Classes

Titra delivered Intellectual Property Service

i r î e LUXEMBOURG

Patent Application ............................................ .................................................. ............................................- (1) L Request

Metallurgical Research Center-Centrum vqor Research ^ 2) in de Metallurgie, Association sans But lûcrâtïf-Vërëhigihg zonder winstoogmerk 47, rue Montoyer B-IÖ4Ö- BRUXELLES

... Represented ...... by .........; ......... 1., ... 1., ......... FREYLINGER. ...... & E ........ MEYERS, ........ Ing ......... cons. in (3) PI .............. 46 f rue du Cimetière LUXEMBOURG Mandatories deposit) this ....... Thirty ...... and ...... .un ...... january ....... mil .... n.eu f ....... hundred ..... eighty ...... neu f (4 ) at ..... 1.5 .. · .0.0 ....... hours, at the Ministry of the Economy and the Middle Classes, in Luxembourg: 1. this request for obtaining a patent d invention relating to: ....., rDispositif ...... "de ....... casting ....... dTün ..... metal '....... in ...... a ....... rîhgô'ifî'ê'fë ............................. ......... ^ .............. of ...... pouring ...... continues ".......... .................................................. ...........................

frârCâlS ^ 2. description in language .................................... i * .... .................................................. ................... of the invention in triplicate; 3. ...................... 2 ......................... .................. drawing boards, in triplicate; 4. the receipt of the taxes paid to the Luxembourg Registration Office on 51 ....... january ...... 1989 ..........

5. the delegation of power, dated ............ Brussels ............................ .............. i 26 ....... january 1989 ..........

6. the successor document (authorization); declares (s) assuming responsibility for this declaration, that the inventor (s) is (are): (6) NAVEAUPaul47, chaussée du Roi Albert 4430 ALLEUR Belgium

... WJ.LMQTTE ............. Stéphan ............. 5..4 .., ........ rue de la Loignerie __________ 4930 ....... CHAUDFONTAINE

_____ Belgium__ claims (s) for the above patent application the priority of one (s) application (s) of (7) ...................... .................. patent ...... d1 invention ___________ filed (s) in (8) Belgium ............... .................................................. .......

I (9) ................ February 3, 1988 ________ __ under N ° (10) 0 8 8 0 0 129 ............. .................................................. .................................................. .................................................. ...............................................

in the name of (11) ........... Center ..... of ...... Research ...... Metallurgical ............ .................................................. .................

elect (elect) domicile for him / her and, if designated, for his / her representative, in Luxembourg ............................. ................................................

__ _________________46, rue du Cimetière _______________________ ß2) requests) the grant of a patent for the invention for the subject described and represented in the abovementioned appendices, with postponement of this grant to ............. .................................................. .................................................. .................................................. .................................month. (13)

The depositor / agent: / ........................... ........ fi ........ .................................................. .................................................. .................................................. ................... (14) / 1 Π. Deposit Minutes

The above application for a patent for invention has been filed with the Ministry of the Economy and the Middle Classes, Department of Intellectual Property, Berlin, dated; 32 "January 1989 / \" \ Pr. The Minister of Economy and the Middle Classes, at ...... 15 ..,. 0.0 hours | g · ’1 iMl.

1¾ ij? J The head of the department ", has intellectual property, V * <*? /.*/ f / -A / - TV, EXPLANATIONS RELATING TO THE FORM TWETOT 1 /, ***** ~ -me * (1) if where applicable "Application for certificate of addition to the main patent, to main patent application No ......... of ............” - (2) enter the surname, first name, profession, address of the applicant, when the applicant is an individual or corporate name, legal form, address of the head office, when the applicant is a legal person - (3) enter the surname. professional representative, industrial property attorney, with special powers, if applicable: "represented by ........... acting as representative" - (4) filing date in full - (5) title of the invention - (6) enter the names, first names, addresses of the inventors or the indication "(see) separate designation (will follow)", when the designation is made or will be done in a separate document, or the indication “not to mention”, when the inventor signs or sign a non-mention document to be attached to a designation * BL 4210

Claim to the priority of the patent application filed in Belgium on February 3, 1988 No 08800129 Descriptive memorandum filed in support of a patent application for invention for: "Device for casting a metal in a continuous casting mold"

Metallurgical Research Center Centrum voor Research in de Metallurgie

Non-profit association Vereniging zonder winstoogmerk 47, rue Montoyer 1040 BRUXELLES Belgium - 1 -

Device for casting a metal in a continuous ingot ingot.

The present invention relates to a device for casting a metal in a continuous casting mold.

The advantage of the casting process is known, with overheating close to 5 ° C. or in the pasty phase for the continuous casting of metals, in particular steel. The description which follows will moreover make special reference to the continuous casting of steel; this choice has no other purpose than that of illustrating the invention in a concrete manner and does not in any way exclude the possibility of using the proposed device to carry out the continuous casting of other metals.

In such a process, the steel undergoes a limited cooling between the casting container, crucible, ladle or distribution basket, and the continuous casting mold; The cooling is carried out in such a way that the steel, having a normal overheating (15 to 50 ° C.) in the pouring vessel, is at a temperature close to its Liquidus temperature or included in its solidification interval when it enters the mold. In the latter case, it contains a solidified fraction, the magnitude of which varies depending on the temperature applied, and therefore presents a pasty state. The casting process with an overheating close to 0 ° C. or in the pasty phase makes it possible to obtain fine and homogeneous structures which reduce the meso- and macroscopic segregations in the cast products.

Already known, in particular from patent LU-A-86,688, a device intended to cool the metal in a controlled manner during its path between the casting container and the continuous ingot mold Ί0. This known device comprises a vertical duct provided externally with cooling means and disposed upstream of the mold, as well as a distributor member disposed substantially at the entrance to this duct. In this device, the vertical duct has at least one section converging in the direction of movement of the metal.

During the tests carried out with this device, however, it appeared that the presence of a converging conduit led to the formation of a layer of solidified metal, of relatively large thickness, on the interior surface of this converging conduit. This layer of solidified metal slows down the transmission of the heat flow, which promotes the increase in the thickness of this layer and can lead to blockage of the passages provided between the distributor member and the vertical duct.

25

The object of the present invention is to provide a device of the aforementioned type which, thanks to a simple but unexpected modification, makes it possible to remedy the drawback which has just been mentioned.

In accordance with the present invention, a device for casting a metal in a continuous casting ingot mold, which comprises a vertical duct externally provided with cooling means and disposed upstream of said ingot mold with respect to the direction of circulation of the metal as well as 'a distributor member disposed substantially at the inlet 35 of said duct, is characterized in that said vertical duct has an outlet section equal to or greater than its inlet section.

- 3 - *, i

According to a particular embodiment of the device of the invention, said vertical duct has a constant internal section over its entire length.

According to another particular embodiment of the device of the invention, said vertical duct has a frustoconical internal profile which diverges in the direction of movement of the metal. In this case, the angle of inclination of the inner wall of said duct relative to the longitudinal axis of the duct is not more than * 45 degrees and is preferably between 3 degrees and 20 degrees.

The vertical duct is preferably made of a material which is a good conductor of heat, in particular copper.

According to an additional characteristic of the device of the invention, said vertical duct is extended by a tubular element, made of refractory material, penetrating into the ingot mold and having a section larger than the section occupied by the metal, so as to avoid clogging .

20

According to another characteristic of the invention, the distributor member is constituted by a substantially horizontal plate; the thickness of said plate decreases from the center towards the edges; it has an outline. exterior such that it provides at least one passage between the edge of the plate and the interior wall of the duct.

Still according to the invention, the continuous casting device further comprises a cap mounted on the inlet end of said conduit and pierced with an opening intended to allow passage to a pouring nozzle. This cap delimits a chamber situated essentially above said distributor member and into which a protective gas can be introduced by appropriate means.

In service, the device of the invention is part of an installation also comprising a ladle or a tundish fitted with a nozzle and a continuous casting mold. It is - 4 - mounted between on the one hand the ladle or the tundish and on the other hand the ingot mold, so that said nozzle opens into the inlet end of the vertical duct, above the 'distributor member, and that the outlet end of the vertical duct, respecti-5ement of the tubular element which extends it opens into said ingot mold for continuous casting. This tubular element may or may not be immersed in the metal present in the mold.

According to an advantageous embodiment of the device of the in-vention, said vertical duct comprises an inlet section of which at least the inner surface is made of a refractory material, and said distributor member is disposed in this section of Entrance.

Thanks to this improved arrangement, the metal flowing from the nozzle is deflected by the distributor member towards the refractory inner wall of said inlet section. This wall does not suffer damage due to the heat flow applied by the metal. However, it can undergo mechanical degradation by erosion in the impact area of the metal. · * »20

In the context of the present invention, this erosion phenomenon can be delayed by using a refractory material which has a high resistance to erosion by liquid metal.

Another means according to the invention for delaying the erosion of said refractory section consists in making the distributor member vertically displaceable in translation. It is thus possible to modify the vertical position of the distributor member with respect to the refractory inlet section, either between two successive casting operations, or possibly during a casting operation. This characteristic makes it possible to distribute the erosion over at least part of the axial length of said refractory inlet section and thus to prolong its service life.

35 In all cases, the liquid metal deflected by the distributing member flows, without appreciable cooling, along the lower part.

, I

- 5 - of the refractory inlet section, then along the copper section where it undergoes the desired cooling.

According to an interesting particularity, the device of the invention 5 comprises means for blowing a gaseous agent inside said vertical duct, below the distributor member.

These means are advantageously constituted by at least one injector mounted on the underside of said distributor member and connected to a suitable source of a gaseous agent, the latter preferably being an inert gas such as argon.

The gaseous agent thus blown allows the pressure to be restored under the distributor member and therefore ensures correct application of the thin layer of meta against the interior wall of the vertical duct.

According to another interesting feature, an element of the vertical duct, for example the inlet section made of refractory material or else the frustoconical member is provided with means intended to impart a rotational movement to the metal passing through said section.

These means are advantageously constituted by inductors generating a rotating electromagnetic field. Rotation by mechanical means is also possible.

The object of the invention will be better understood with the aid of the following description of a preferred embodiment of the device of the invention, with reference to the accompanying drawings in which FIG. 1 shows an elevation view of a casting device in cross section; and FIG. 2 illustrates a variant in which the vertical duct is extended by a tubular element penetrating into the ingot mold for continuous casting.

In these figures, analogous elements are designated by the same reference numerals.

- 6 -

Figure 1 shows, in elevation, a casting device according to the invention, mounted between a continuous casting mold 1 and a ladle or a casting basket symbolized by the nozzle 2. A divergent frustoconical conduit 3 of copper is mounted on the ingot mold 1; this 5 duct is provided with water cooling shown diagrammatically by the arrows 4 and 5. At the upper end of this duct 3 is arranged a distributor member in the form of a plate 6 whose thickness decreases from the center towards the edges. The shape of this plate is adapted to that of the section of the conduit 3.

10

The conduit 3 is lined with a cap 7, made of refractory material, delimiting a chamber 8 above the distributor plate 6. This cap is provided, in its cover, with an opening in which the nozzle 2 engages; the cap 7 is also provided with a system 9 for introducing a gas under pressure into the chamber 8. Such a gas introduction system is well known per se and is not described in detail here- *

FIG. 2 illustrates a variant of the device of the invention, in which the vertical duct 3 is extended by a tubular element 10 penetrating inside the ingot mold 1. If necessary, the lower end of this tubular element 10 can be immersed in the metal in the mold. For the rest, this variant corresponds entirely to the representation of FIG. 1.

25

The mode of operation of this device is as follows;

The conduit 3 is mounted on the mold 1, then the distributor plate 6 and the cap 7 are in turn put in place. The ladle or the tundish, not shown, is then brought into position so as to engage the nozzle 2 in the opening provided in the cover of the cap 7. The nozzle 2 is opened and the superheated liquid steel s' flows through it on the distributor plate 6. Due to the inclination of the upper surface of the plate 6, the steel flows 35 towards the periphery of the plate 6, then through the passages formed between the projections of centering of the plate.

* - 7 - The Liquid steel thus flows in a thin layer spreading over the interior wall of the duct 3. The cooling of the duct ensures the elimination of the steel overheating and, if the cooling is very intense, causes the appearance of a solid fraction which makes the steel pasty as it enters the ingot mold 1. The introduction of a protective gas under pressure, for example of argon, into the chamber 8 causes an overpressure in this chamber and prevents any entry of air in contact with the liquid steel.

The device of the invention has a large heat exchange surface between the cooled pipe and the liquid steel; the high flow speed of the latter along the wall of the duct makes it possible to achieve a high density of heat flow. It would not, moreover, depart from the scope of the invention to increase this density of flux by imparting to the duct a rotational movement around its axis.

The device of the invention is simple, compact and robust. It has great operational safety, in particular due to the almost total absence of solidified metal on the inner wall of the divergent vertical duct.

Claims (10)

1. Device for casting a metal into a continuous casting mold / which comprises a vertical duct (3) externally provided with cooling means and disposed upstream of said mold (1) relative to the direction of circulation of the metal thus that a distributor member (6) disposed substantially at the inlet of said duct, characterized in that said vertical duct has an outlet section equal to or greater than the inlet section. 2. Casting device according to claim 1, characterized in that the said vertical duct (3) has a divergent conical inner profile in the direction of flow of the metal. 3. Casting device according to claim 2, characterized in that the angle of inclination of the inner wall of said vertical pipe with respect to the longitudinal axis of the pipe is not greater than 45 degrees and is preferably understood. between 3 degrees and 20 degrees. 4. Casting device according to either of claims 1 20 to 3, characterized in that said vertical duct is extended by a tubular element (10) penetrating into the mold. 5. Casting device according to either of claims 1 to 4, characterized in that the distributor member consists of a substantially horizontal plate, said plate having a thickness decreasing from the center towards the edges and a contour. as it spares at least one passage between the edge of the plate and the interior wall of the conduit. 6. pouring device according to either of claims 1 to 5, characterized in that it comprises a cap (7) mounted on the end of said entry conduit and pierced with an opening intended to deliver passage to a pouring nozzle (2). / .. .. · »* s - 9 - 7. Casting device according to either of claims 1 to 6, characterized in that the duct comprises an inlet section of which at least the internal surface is made of a refractory material, and in that the the distributor member is disposed in said 5 inlet section. 8. A casting device according to claim 7, characterized in that said distributor member is movable vertically in translation in said inlet section. 10 9. A casting device according to either of claims 1 to 8, characterized in that it comprises means for blowing a gaseous agent inside said vertical duct, below said distributor member. 15 10. Casting device according to either of claims 1 to 9, characterized in that said vertical duct is provided with means intended to impart a rotational movement to the metal which passes through it.