Indian Patents. 201032:CASTING NOZZLE FOR THIN-STRIP CASTING PLANTS

Title of Invention	CASTING NOZZLE FOR THIN-STRIP CASTING PLANTS
Abstract	The invention relates to a nozzle for thin-strip casting plants, in particular for steel strip.In such casting plants, the liquid steel is to be applied on to a carrier via the nozzle which forms a pouring gap. At least one primary coil and at least one secondary coil are arranged on the nozzle, the secondary coil being water-cooled and projecting into the region of the pouring gap.

Full Text	CASTING NOZZLE FOR THIH-STRIP CASTING PLAMTS The invention relates to a casting nozzle for thin-strip casting plants, in particular for casting thin steel strip A nozzle for casting thin steel strip is known from DE 37 07 897, wherein the nozzle forms a rear dam, which borders on a moveable carrier, and a front dam, a pouring gap between the rear dam and the front dam being defined in the direction of the carrier. A revolving steel belt serves as the carrier. Nozzles of this kind are usually of a refractory material which is subjected to a certain degree of wear at the high temperatures of the steel melt, with the result that the shape of the pouring gap may change during casting, the nozzle, at any rate, requiring replacement after a certain service life. It is an object of the invention to provide an improved nozzle construction, in which the wear is reduced to a minimum and in which it is possible for the melt to be heated in the jregion of the pouring gap. According to the invention, at least one primary inductor and at least one secondary inductor are arranged on the nozzle, at least one secondary inductor being water-cooled and projecting into the region of the pouring gap. Accordingly, the present invention provides a casting nozzle for thin-strip casting plants, comprising a rear dam which rests on a carrier for the thin strip, which carrier is movable in the direction of transportation, a front dam which defines the pouring gap relative to the carrier in the direction of transportation, at least one primary inductor and at least one secondary inductor being provided, at least one secondary inductor being water-cooled and projecting into the region of the pouring gap. As a result of the use of a primary inductor and a secondary inductor, as separate components for generating an electromagnetic field which extends into the region of the melt, it is possible, firstly to ensure that the melt in the region of the secondary inductor does not reach up to the wall of the primar> inductor, which could possibly result in electric short-circuits. Secondly, it is possible for an eddy current field to be induced in the melt itself by the currents induced in the secondary inductor, thereby permitting heating of the melt in the region of the pouring opening. As a result hereof, it is possible to prevent that the pouring opening is altered by incrustations of solidified melt. In addition, the electromagnetic forces in the melt result in a displacement of the melt away from the secondary inductor, which is also advantageous for preventing incrustations. The principle described is used in the known cold crucible technique for melting metals in water-cooled crucibles. According to a preferred emibodiment, the secondary inductor comprises a plurality of sections which are electrically insulated relative to one another. As a result hereof, each section acts as a separate secondary inductor. According to a further preferred embodiment, a plurality of outflow openings, which are disposed next to one another in the direction of the thin-strip breadth, for the melt are provided between the rear and front dams. The above provides for a more uniform distribution of the melt across the breadth of the pouring gap (thin-strip breadth). The outflow openings are produced by a corresponding shaping of the rear dam in the direction of transportation, or by a corresponding shaping of the front dam in a direction opposite to the direction of transportation. According to a further preferred embodiment, a secondary-inductor in the rear dam comprises a plurality of insulated sections, each having an inlet and an outlet for cooling water, the individual sections being designed to be dovetailed or arrow-shaped or linear, in order to form the outflow openings for the melt. Provided in the interior of the sections is, in particular, a flow-guiding plate, such that a positive guiding is ensured between the inlet and the outlet at that end of the sections disposed away from the pouring gap and up to that top region of the sections which faces the pouring gap. According to another preferred development, electrically insulated sections of a secondary inductor, comprising an inlet and an outlet for cooling water, are arranged in the region of the front dam, wherein, in the top region of the sections, i.e. at the point where the front dam borders on the pouring gap, the sections are designed to be dovetailed or arrow-shaped or linear, for forming outflow openings. In so far as dovetailed or arrow-shaped forms are mentioned in this regard for the front or rear dams in the region of the outflow openings, it is intended to include any other shape, in particular also semi-circular, etc. Likewise, also included is a corresponding shaping of the front and rear dams, e.g. it is also possible to provide circular outflow openings. The sections in the front dam, which are insulated relative to one another, are preferably also provided in the interior with flow-guiding plates between the inlet and the outlet. An exemplified embodiment of a nozzle for thin-strip casting plants is diagrammatically illustrated in the drawings. Figure 1 shows a vertical section of a nozzle, in which the secondary inductor 22 in the region of the rear dam 2 comprises individual sections having dovetailed ends. The vertical section extends through the middle of the dovetail 23. The rear dam 2 is mounted on a carrier 1, in particular on an endless belt revolving around rollers. A pouring gap 4 is formed between the rear dam 2 and the front dam 3. A primary inductor 21 borders on the secondary inductor 22. It is possible for the liquid steel to flow out into the free region between the dovetail 23 and the front dam 3 from the damming-up region 5 and into the solidification region 6, in the direction of flow as indicated by the arrow 7. A flow-guiding plate 24 is arranged in the section 22. The secondary inductor 22 is covered by refractory material 25 in the direction of the damming-up region 5. The inductors 22, 23 are water-cooled and are preferably of copper. The primary inductor 21 is powered by a high frequency. In the variation illustrated in Figure 2, the front dam 3 is formed by a plurality of secondary inductors 32, which are electrically insulated relative to one another and in which a primary inductor induces an electric current. The primary inductor 31 and the secondary inductor 32 are water-cooled and the primary inductor 31 is powered by a high frequency. The secondary inductor 32 extends to a point beyond the tip of the dovetail of the secondary inductor 22. WE CLAIM: 1. A casting nozzle for chin-strip casting plants, comprising a rear dam which rests on a carrier for the thin strip, which carrier is movable in the direction of transportation a front dam which defines the pouring gap relative to the carrier in the direction of transportation, at least one primary inductor and at least one secondary' inductor being provided, at least one secondary inductor being water-cooled and projecting into the region of the pouring gap. 2. The casting nozzle as claimed in claim I, wherein a secondary inductor comprises a plurality of sections which are insulated relative to one another. 3. The casting nozzle as claimed in claim 2, wherein a plurality of outflow openings is provided between the rear dam and the front dam the outflow openings being disposed next to one another in the direction of the thin-strip breadth. 4. The casting nozzle as claimed in claim 3, wherein a secondary inductor in the rear dam comprises electrically insulated sections having an inlet and an outlet for cooling water and the sections are designed to be dovetailed or arrow-shaped or linear, for producing the outflow openings. 5. The casting nozzle as claimed in claim 3, wherein a secondary inductor in the front dam comprises electrically insulated sections having an inlet and an outlet for cooling water, and the sections are designed to be dovetailed or arrow-shaped or linear, for producing the outflow openings. 6. A casting nozzle for thin-strip casting plants, substantially as herein described with reference to the accompanying drawings.

Full Text

CASTING NOZZLE FOR THIH-STRIP CASTING PLAMTS
The invention relates to a casting nozzle for thin-strip casting plants, in particular for casting thin steel strip
A nozzle for casting thin steel strip is known from DE 37 07 897, wherein the nozzle forms a rear dam, which borders on a moveable carrier, and a front dam, a pouring gap between the rear dam and the front dam being defined in the direction of the carrier. A revolving steel belt serves as the carrier.
Nozzles of this kind are usually of a refractory material which is subjected to a certain degree of wear at the high temperatures of the steel melt, with the result that the shape of the pouring gap may change during casting, the nozzle, at any rate, requiring replacement after a certain service life.
It is an object of the invention to provide an improved nozzle construction, in which the wear is reduced to a minimum and in which it is possible for the melt to be heated in the jregion of the pouring gap.
According to the invention, at least one primary inductor and at least one secondary inductor are arranged on the nozzle, at least one secondary inductor being water-cooled and projecting into the region of the pouring gap.

Accordingly, the present invention provides a casting nozzle for thin-strip casting plants, comprising a rear dam which rests on a carrier for the thin strip, which carrier is movable in the direction of transportation, a front dam which defines the pouring gap relative to the carrier in the direction of transportation, at least one primary inductor and at least one secondary inductor being provided, at least one secondary inductor being water-cooled and projecting into the region of the pouring gap.
As a result of the use of a primary inductor and a secondary inductor, as separate components for generating an electromagnetic field which extends into the region of the melt, it is possible, firstly to ensure that the melt in the region of the secondary inductor does not reach up to the wall of the primar> inductor, which could possibly result in electric short-circuits. Secondly, it is possible for an eddy current field to be induced in the melt itself by the currents induced in the secondary inductor, thereby permitting heating of the melt in the region of the pouring opening. As a result hereof, it is possible to prevent that the pouring opening is altered by incrustations of solidified melt. In addition, the electromagnetic forces in the melt result in a displacement of the melt away from the secondary inductor, which is also advantageous for preventing incrustations. The principle described is used in the known cold crucible technique for melting metals in water-cooled crucibles.

According to a preferred emibodiment, the secondary inductor comprises a plurality of sections which are electrically insulated relative to one another. As a result hereof, each section acts as a separate secondary inductor.
According to a further preferred embodiment, a plurality of outflow openings, which are disposed next to one another in the direction of the thin-strip breadth, for the melt are provided between the rear and front dams.
The above provides for a more uniform distribution of the melt across the breadth of the pouring gap (thin-strip breadth). The outflow openings are produced by a corresponding shaping of the rear dam in the direction of transportation, or by a corresponding shaping of the front dam in a direction opposite to the direction of transportation.
According to a further preferred embodiment, a secondary-inductor in the rear dam comprises a plurality of insulated sections, each having an inlet and an outlet for cooling water, the individual sections being designed to be dovetailed or arrow-shaped or linear, in order to form the outflow openings for the melt. Provided in the interior of the sections is, in particular, a flow-guiding plate, such that a positive guiding is ensured between the inlet and the outlet at that end of the sections disposed away from the pouring gap and up to that top region of the sections which faces the pouring gap.

According to another preferred development, electrically insulated sections of a secondary inductor, comprising an inlet and an outlet for cooling water, are arranged in the region of the front dam, wherein, in the top region of the sections, i.e. at the point where the front dam borders on the pouring gap, the sections are designed to be dovetailed or arrow-shaped or linear, for forming outflow openings.
In so far as dovetailed or arrow-shaped forms are mentioned in this regard for the front or rear dams in the region of the outflow openings, it is intended to include any other shape, in particular also semi-circular, etc. Likewise, also included is a corresponding shaping of the front and rear dams, e.g. it is also possible to provide circular outflow openings. The sections in the front dam, which are insulated relative to one another, are preferably also provided in the interior with flow-guiding plates between the inlet and the outlet.
An exemplified embodiment of a nozzle for thin-strip casting plants is diagrammatically illustrated in the drawings.
Figure 1 shows a vertical section of a nozzle, in which the secondary inductor 22 in the region of the rear dam 2 comprises individual sections having dovetailed ends. The vertical section extends through the middle of the dovetail 23. The rear dam 2 is mounted on a carrier 1, in particular on an endless belt revolving around rollers.

A pouring gap 4 is formed between the rear dam 2 and the front dam 3. A primary inductor 21 borders on the secondary inductor 22. It is possible for the liquid steel to flow out into the free region between the dovetail 23 and the front dam 3 from the damming-up region 5 and into the solidification region 6, in the direction of flow as indicated by the arrow 7. A flow-guiding plate 24 is arranged in the section 22. The secondary inductor 22 is covered by refractory material 25 in the direction of the damming-up region 5. The inductors 22, 23 are water-cooled and are preferably of copper. The primary inductor 21 is powered by a high frequency.
In the variation illustrated in Figure 2, the front dam 3 is formed by a plurality of secondary inductors 32, which are electrically insulated relative to one another and in which a primary inductor induces an electric current. The primary inductor 31 and the secondary inductor 32 are water-cooled and the primary inductor 31 is powered by a high frequency. The secondary inductor 32 extends to a point beyond the tip of the dovetail of the secondary inductor 22.

WE CLAIM:
1. A casting nozzle for chin-strip casting plants, comprising a rear dam which rests on a carrier for the thin strip, which carrier is movable in the direction of transportation a front dam which defines the pouring gap relative to the carrier in the direction of transportation, at least one primary inductor and at least one secondary' inductor being provided, at least one secondary inductor being water-cooled and projecting into the region of the pouring gap.
2. The casting nozzle as claimed in claim I, wherein a secondary inductor comprises a plurality of sections which are insulated relative to one another.
3. The casting nozzle as claimed in claim 2, wherein a plurality of outflow openings is provided between the rear dam and the front dam the outflow openings being disposed next to one another in the direction of the thin-strip breadth.
4. The casting nozzle as claimed in claim 3, wherein a secondary inductor in the rear dam comprises electrically insulated sections having an inlet and an outlet for cooling water and the sections are designed to be dovetailed or arrow-shaped or linear, for producing the outflow openings.
5. The casting nozzle as claimed in claim 3, wherein a secondary inductor in the front dam comprises electrically insulated sections having an inlet and an outlet for cooling water, and the sections are designed to be dovetailed or arrow-shaped or linear, for producing the outflow openings.

6. A casting nozzle for thin-strip casting plants, substantially as herein described with reference to the accompanying drawings.

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Patent Number

201032

Indian Patent Application Number

1184/MAS/1997

PG Journal Number

08/2007

Publication Date

23-Feb-2007

Grant Date

28-Jun-2006

Date of Filing

03-Jun-1997

Name of Patentee

M/S. MANNESMANN AG

Applicant Address

GERHARD-LUCAS-STRASSE 3-5,D-31226 PEINE

Inventors:

#	Inventor's Name	Inventor's Address
1	PROF. KLAUS SCHWERDTFEGER,	ZEPPELINSTR. 28, D-38640 GOSLAR;
2	DR. ING. KARL-HEINZ SPRITZER	STETTINER STR. 2, D-38678 CLAUSTHAL-ZELLERFELD;
3	PROF. DR. ING WOLFGANG REICHELT,	AM BENDMANNSFELD 52, D-47447 MOERS;
4	DR. ING, ULRICH URLAU,	AM FELDRAIN, D-47445 MOERS;
5	DR JOACHIM KROOS,	SCHUNTERWEG 7, D-38527 MEINE
6	DR. MICHAEL BRUHL,	HOLTEISTR. 3, D-38304 WOLFENBUTTEL;

PCT International Classification Number

B22D 11/06

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	196 36 697.6	1996-09-09	Germany
2	196 22 924.3	1996-06-07	Germany