LU87448A1 - DEVICE FOR COOLING AND AGITATING METAL DURING CASTING - Google Patents

Description

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8n 1 * 7 / L - GRAND DUCHY OF LUXEMBOURG

...... i η Ό * -Mister Minister of „9 ........ ié.VXier ....... 19.8.9 ....... 'of the Economy and Middle Classes

Title issued Intellectual Property Service

i dr e drunk .............................................. .......... fêàÿ LUXEMBOURG

Patent Application ............................................ .................................................. .............. — ................................... ............. (1) I. Application

Center .... de ..... Recherches ..... l ^ talliirgi ^ jes-CmtLmm ..... y: c) or ..... Research ..... in .... .de ... Metallur- (2) gia, ...... ass.Qciâtion ... sans .... hut .... ^ ..... 47_rus________

Mpntover, ..... B-1040 ..... Bruxelles, represented by Jean Waxweiler, 55 rue des Bruyères, Howald ..................... .................... ^ 3 ^ remove (s) this new one. February. nineteen ....... cen.t ...... auatr..ev: ing.trn.eu.f .................... ........................ (4) at 15.00 ... hours, at the Ministry of the Economy and the Middle Classes, in Luxembourg: 1. the present request for obtaining a patent of invention concerning: D.is.p.Qs.it.lf ....... for ...... cool ...... and ...... shake ....... a ...... m.é..tal ...... during ....... the ....... ................... (5) casting ........................... .................................................. .................................................. .................................................. .................................................. ...................................

2. description in French ........................................... ............... of the invention in triplicate; 3. ........................ 3 ....................... .................... drawing boards, in triplicate; 4. the receipt of the taxes paid to the Luxembourg Registration Office, on 99. · 0 2.1989 ............................ ..

5. the delegation of power, dated ......................................... ..... on .................... 9.A ·.? ..? .. * 9: .......... ..................; 6. the successor document (authorization); declare (s) assuming responsibility for this declaration, that the inventor (s) is (are); (6) FRANÇOIS Hubert., 148, rue du Cimetière, B-4300 Years ................................. ..................................

WILMOTTE Stephan, 54, rue de la Loignerie, B-493Ô Chaudfontaine claims (s) for the above patent application the priority of one (s) request (s) of (7) .......... ..............................patent------------------- ------------------------------------------------- filed (s) in (8) —Belgium ......................................... ........................................

on (9) ......... ll..i.é .. ¥ rier ... JL9..8.8 .________________________________________________________________________________________________________________________________________________________________________ under N ° (10) 08.800162 _____________________________________________________________________________________________________________________________________________________________ on behalf of (11) Center de Bedierdies Metallurgiques-Centrum voor Researcli in de Meta] elects) domicile for him / her and, if designated, for his / her representative, in Luxembourg ...................... .................................................. .lunçp 5.5 ...... rue ....... dea „.JB.ruy.èr.es., ....... H.ow.ald ____________________________________________________________________________________________________________________ (12) seeks delivery of a patent for the subject-matter described and represented in the abovementioned appendices, with postponement of this issue to 1 ... · .............. L ..... .Zj ______ ______________________________________________________________________________________________________month. (13)

The chief representative: _______________________________________________________________________________________________________________________________________________________________________________________ (14) Π. Deposit Minutes

The above application for a patent for invention has been filed with the Ministry of the Economy and the Middle Classes, Intellectual Property Department, Luxembourg, dated; 09 .02.1989 /.f^ ·.

i ây \ Pr. the Minister of Coastal and Middle Classes, at 3.00 pm ............. hours | J \ i \ yrp. d.

T. U 5¾ .¾.) The head of the intellectual property department,

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A68007_, · "_A) / \ _ EXPLANATIONS CONCERNING THE FORM ÖS '& mftT / // | (I) if applicable" Request for certificate of addition to the main patent, to the main patent application No. - .. ... DD: .. of ............ "- (2) enter the last name, first name, profession.

address of the applicant, when the latter is an individual or corporate name, legal form, address of the head office, when the applicant is a legal person- (3) enter f) λ λ • 'jv les nom. first name, address of professional representative, industrial property attorney, with special powers, if applicable: "represented by ........... acting as representative" ♦ s / / / j - (4) date of deposit in full - (5) title of the invention - (6) enter the names, first names, addresses of the inventors or the indicatton "(see) separate designation (will follow when the desi -

The declaration is made or will be made in a separate document, or the indication ”do not mention '*, when the inventor signs a non-mention document to be attached to a designation PRIORITY CLAIMS Filing of the patent application in Belgium on February 11 1988 UNDER number 08800162

DESCRIPTIVE MEMORY FILED IN SUPPORT OF A PATENT INVENTION APPLICATION IN THE GRAND DUCHY OF LUXEMBOURG

Metallurgical Research Center-Centrum voor Research in de Metallurgie, non-profit making association - vereniging zonder winstoogmerk 47, rue Montoyer B-1040 Bruxelles | »o * rs Device for cooling and stirring a metal during casting - 1 -

Device for cooling and stirring a metal during casting.

The present invention relates to a device for simultaneously cooling and stirring a metal during casting, in particular the steel flowing between a casting nozzle and a continuous casting ingot mold.

5

To fix the ideas, the description which follows will be specially devoted to The continuous casting of steel. It should however be emphasized that this particular application has only a simple example value and that the device of the invention can be used in the context of any casting process, for example in a mold or in an ingot mold, and with any metal displaceable by means of an electromagnetic field.

It is currently well known that it is advantageous to cast the steel with an overheating close to 0 ° C. or even in the pasty phase. For this purpose, the steel leaving the pouring container is cooled either to a temperature close to its liquidus temperature but nevertheless higher than this, or to a temperature within its solidification range. This ensures at least the elimination of the overheating of the steel, and possibly the appearance in steel of a solidified fraction, the importance of which depends on the cooling applied. As it enters the mold, the steel thus presents a state which makes it possible to obtain fine and homogeneous structures and to reduce the meso- and macroscopic segregations in the cast products.

Already known, in particular from patent LU-A-86,688, a device for casting a metal such as steel in the pasty phase. This known device essentially comprises an externally vertical duct 10 provided with cooling means, a distributor member located substantially at the entrance to the vertical duct and possibly one or more inductors surrounding a refractory section preceding the vertical duct. In this known device, the cooling means and the inductors, or more generally the metal stirring means 15 are separate, which results in a large size of the casting apparatus and which does not allow to submit the same volume of metal simultaneously with stirring and cooling. In addition, the inductors are distant from the cast metal, which limits the degree of agitation that can be achieved with this device.

20

The present invention proposes to remedy these drawbacks by revealing a particular device allowing simultaneous controlled cooling and effective stirring of the metal during casting.

25

According to the present invention, a device for casting a metal comprising a vertical duct provided with means for cooling and means for stirring the metal during casting and a metal distribution member located substantially at the entrance to said duct. vertical, is characterized in that said cooling means are located entirely in the wall of said vertical duct and in close proximity to the interior surface of said wall, and in that the interior surface of said wall is coated with a thin layer of '' an erosion resistant refractory material.

- 3 -

According to a particular embodiment, said cooling means comprise a plurality of tubes oriented in the longitudinal direction of said vertical duct and distributed along the inner periphery of said vertical duct, said tubes being traversed by a coolant which is preferably water.

According to an additional characteristic of the device of the invention, said cooling means further comprise a plurality of chambers formed in the wall of said vertical duct 10, parallel to said longitudinal tubes and each communicating with the internal volume of at least one of said tubes by passages distributed along the length of said vertical duct.

Said longitudinal tubes preferably have a front face, that is to say a face turned towards the inside of said vertical duct, curved so as to constitute a cylindrical surface. This cylindrical surface can be discontinuous if the tubes are not joined; in this case, said cylindrical surface is advantageously supplemented by suitable elements, which maintain the spacing of said 20 tubes. These elements can be made for example of refractory concrete, in order to further ensure the thermal independence of said tubes.

According to another advantageous embodiment of the device of the invention, said longitudinal tubes are made of a material which is good conductor of electricity and they are connected to a source of electric current so as to generate an electromagnetic field rotating inside the vertical duct.

In this case, the spacers arranged between said tubes will be made of an electrically insulating material, in order to further preserve the electrical separation of these tubes.

Also according to an advantageous characteristic, the thin layer of refractory material covering the interior surface of said vertical duct has a thickness which does not exceed 5 mm, in order to bring the steel to be cooled as close as possible to the surface of the cooling tubes.

Other features and advantages of the invention will become apparent on reading the detailed description which is given below by way of example. This description relates to a preferred embodiment of the device of the invention, which is illustrated by the appended drawings, in which FIG. 1 shows a general view, partially in section, of a casting installation comprising a device in accordance with invention; Figure 2 shows a cross section through a cooling device according to the invention, showing the circumferential arrangement of the cooling means; 15 and FIG. 3 illustrates, in two longitudinal half-sections, the radial and longitudinal arrangement of the cooling means in the device of the invention.

20 The above figures 1 to 3 obviously constitute schematic representations, in which only the elements directly necessary for the understanding of the invention have been reproduced voluntarily. Identical or analogous elements are also designated by the same reference numerals in all the figures.

25

In Figure 1, to which reference is now made, there is shown, partially in section, a casting installation of a type known per se, used in particular for the continuous casting of steel in the pasty phase. This installation comprises an ingot mold 30 for continuous casting 1, a pouring nozzle 2 fitted to a casting container which is not otherwise shown, and an intermediate cooling device which notably comprises a vertical duct 3, a distributor member 4 and an element tubular 5. The distributor member 4 intercepts the steel jet flowing from the nozzle 2 and distributes it over the inner surface of the vertical duct 3. In FIG. 1, the distributor member 4 is shown in FIG. outside of the vertical duct 3, for the sake of clarity in the drawing, because the vertical duct 3 is seen in elevation. It is clear that this distributor member is preferably located inside said vertical duct, substantially at the entrance thereof, to best ensure the desired distribution of the cast steel. The tubular element 5 extends the vertical conduit 3 downwards and its lower end can be immersed in the steel which is in the ingot mold 1. The tubular element 5 is shown here with a converging longitudinal profile; It goes without saying that, as is well known, this tubular element 10 could be cylindrical or divergent or even have any longitudinal profile, without altering the scope of the present invention.

The vertical duct 3 has a particular structure which constitutes the object of the present invention. This particular structure is illustrated in FIGS. 2 and 3. It makes it possible to proceed either only with cooling or simultaneously with cooling and stirring of the steel.

Referring to FIG. 2, which represents a cross section along the line 2-2 of FIG. 3, it can be seen that the vertical duct 3 comprises a cylindrical body 6 whose internal surface is provided with longitudinal notches 7 separated by teeth 8. The notches 7 are preferably equidistant, of the same circumferential width and 25 of the same radial depth. The head of the teeth 8 has a curved surface which is a portion of the initial internal cylindrical surface of the vertical conduit 3. In front of each of these notches 7 is disposed a longitudinal tube 9, having a generally trapezoidal cross section delimited by two side walls radial 30 and two curved walls, respectively front and rear. Each tube 9 is supported by the longitudinal edges of its rear face, on the head of the teeth 8 delimiting the corresponding notch 7. Said rear face of each tube 9 is pierced with holes 10, distributed over the length of the tube 9, which make the interior of the tube 9 communicate with the notch 7.

- 6 -

The curved faces, front and rear, of the tubes 9 are portions of cylinders coaxial with the vertical duct 3, the rear faces further having a curvature equal to the curvature of the cylindrical surface formed by the head of the teeth 8.

5

The front faces of the tubes 9 thus form a discontinuous cylindrical surface. Spacer blocks 11 are housed between the tubes 9, at the level of their front faces, in order to maintain the desired spacing between these tubes, to complete the cylindrical surface 12 formed by 10 said front faces and possibly to ensure the thermal independence of the tubes 9.

Finally, a sheath 13, made of refractory material, of small thickness, is applied to the cylindrical surface 12. The refractory material 15 constituting the sheath 13 must have a high mechanical resistance, since the thickness of the sheath is preferably not greater than 5 mm, so as not to significantly reduce the cooling efficiency. For this purpose, the refractory material of the sheath 13 advantageously has good thermal conductivity as well as a high resistance to thermal shock. One can in particular use a refractory material consisting of alumina (Al ^ O ^), magnesia (MgO), boron nitride (BN) and / or zirconia (Zr O ^).

The sheath 13 may consist of a thin tube, which is laid by shrinking on said cylindrical surface. It would not, however, depart from the scope of the invention for this sheath to be produced by any other means known per se, for example by projection or molding in place.

Inside the tubes 9, are arranged elongated bars 14 30 applied to the rear face of the tubes and pierced with passages 15 which extend the holes 10. These bars 14, only two of which are shown, occupy part of the interior section tubes 9, leaving free, in each tube, a channel 16 internally running along the front face and possibly the side faces. The coolant is thus forced to circulate along these faces and therefore to cool them effectively. These bars 14 can obviously have any cross section, their role being, as has just been indicated, to make the cooling of the front face of the tubes 9 as efficient as possible. The bars 14 are advantageously made of plastic, both to facilitate their bonding and to avoid the risk of corrosion.

FIG. 3 shows a longitudinal section of the vertical duct 3, taken along the broken line 3-0-3 'of FIG. 2.

10 The left half of FIG. 3 corresponding to the half-section 3-0, shows the arrangement of the spacer blocks 11 relative to the refractory sheath 13 and to the body 6 of the vertical duct.

The right half of FIG. 3, which corresponds to the half-section 0-3 ′, 15 shows the thin refractory sheath 13, applied to the front face 12 of a tube 9. Immediately behind this front face 12 and the running along the entire height of the vertical duct 3, there is a channel 16 which communicates by passages 15 formed in a bar 14 and by holes 10 drilled in the rear face of the tube 9, with a notch 7 cut in the body 6 vertical duct 3.

The notches 7 communicate with an annular chamber 17, located at the bottom of the vertical duct 3, which is itself connected to a system 18 for supplying coolant. At the upper part of the vertical duct 3, the channels 16 open into a second annular chamber 19, which is connected to a system 20 for removing the coolant.

Without departing from the scope of the invention, the device illustrated in FIGS. 2 and 3 can be modified so as to also be able to stir the cast steel.

To this end, the body 6 is made of a stack of sheets of a ferromagnetic material, for example steel, and the tubes 9 are made of a material which is a good conductor of electricity, in particular copper. At the bearing surfaces of the tubes 9 on the teeth 8, - 8 is interposed an appropriate electrical insulator 21, and the spacer blocks 11 as well as the refractory sheath 13 are made of an electrically insulating material. The tubes 9 are connected to the poles of an electric current source so as to produce an electromagnetic field 5 rotating in the central passage of the vertical conduit 3.

The device of the invention operates as follows.

The steel flowing from the nozzle 2 is deflected by the distributor member 4 so as to form a thin layer flowing along the refractory sheath 13, inside the vertical duct 3.

A pressurized coolant, usually water, is introduced into the lower annular chamber 17, from which it gains the notches 7 and then the channels 16, through the holes 10 and the passages 15. These cooling channels 16 are very close to the steel which flows along the sheath 13. The cooling of the steel is effective and can be easily controlled.

20

In the cases where the tubes 9 are connected to a source of electric current, the front face 12 of the tubes of the inductor is very close to the steel flowing along the sheath 13, so that this steel can be put in movement by means of a small amount of electrical energy.

In both cases, the water leaving the cooling channels 16 is collected in the upper annular chamber 19 from where it is evacuated by the system 20. After appropriate cooling, this water 30 can moreover be recycled in the system d '' feed 17, 18.

The short distance between the front face of the cooling tubes and the steel allows greater cooling efficiency to be achieved.

- 9 -

In addition, the short distance between the tubes of the inductor and the steel, as well as the presence of a laminated magnetic yoke, around the conductors 9 makes it possible to achieve a higher level of induction in the acfer. This results in a higher transmitted torque, and therefore higher shear rates and thus better fluidity of the cast steel, even in the partially solidified state.

Claims (10)

1. A device for casting a metal, comprising a vertical duct provided with means for cooling and means for stirring the metal during casting, and a metal distribution member located substantially at the entrance of said vertical duct, characterized in that said cooling means are located entirely in the wall of said vertical duct and in close proximity to the interior surface of said wall, and in that the interior surface of said wall is coated with a thin layer of refractory material resistant to erosion. 10 2. Device according to claim 1, characterized in that said cooling means comprise a plurality of tubes oriented in the longitudinal direction of said vertical duct and distributed along the inner periphery of said vertical duct, and in that said tubes are traversed by a cooling liquid. 3. Device according to claim 2, characterized in that said cooling means further comprise a plurality of chambers formed in the wall of said vertical duct, parallel to said longitudinal tubes, and in that said chambers each communicate with the internal volume d 'at least one of said tubes by passages distributed along the length of said vertical duct. 25 4. Device according to either of Claims 2 and 3, characterized in that the said longitudinal tubes have a front face, that is to say a face turned towards the inside of the said vertical duct, curved into a portion of cylindrical surface, all of the front faces of said tubes thus forming a discontinuous cylindrical surface coaxial with said vertical duct. - 11 - 5. Device according to claim 4, characterized in that there are provided, between said longitudinal tubes, spacing elements including the front face, that is to say the face turned towards the interior of said vertical duct, is curved into a portion of cylindrical surface 5 and complete said discontinuous cylindrical surface. 6. Device according to either of claims 2 to 5, characterized in that the said longitudinal tubes are made of a material which is a good conductor of electricity and in that they are connected to a source of electric current so as to generate an electromagnetic field rotating inside said vertical duct. 7. Device according to either of claims 3 to 6, characterized in that said longitudinal tubes contain longitudinal bars located in the immediate vicinity of the interior surface of said vertical duct, and in that said bars are provided with passages making said longitudinal channels communicate with said chambers. HO 8. Device according to either of claims 3 to 7, characterized in that said chambers are connected to a source of coolant and in that the interior volume of said longitudinal tubes is connected to evacuation means Coolant. 25 9. Device according to either of claims 1 to 8, characterized in that said thin layer of refractory material consists of a tube laid by hooping on the inner surface of said vertical duct. 30 10. Device according to either of claims 1 to 9, characterized in that the thickness of said thin layer of a refractory material is at most equal to 5 mm.