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Publication numberUS3727672 A
Publication typeGrant
Publication dateApr 17, 1973
Filing dateDec 4, 1970
Priority dateApr 22, 1969
Publication numberUS 3727672 A, US 3727672A, US-A-3727672, US3727672 A, US3727672A
InventorsGrenfell H
Original AssigneeSteel Co Of Wales Ltd
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Formation of steel strip
US 3727672 A
Abstract
The present invention relates to a process for the continuous casting of metal strip, which process comprises imparting an electrostatic charge of at least 80,000 volts to a stream of molten metal, passing the stream of metal through a nozzle into an inert atmosphere and allowing the stream leaving the nozzle to atomise to a fine spray, collecting the spray droplets on a cool receiving surface to form a layer of metal on said surface and continuously stripping the layer of metal from said surface.
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Description  (OCR text may contain errors)

United States Patent 1191 Grenfell 1 FORMATION OF STEEL STRIP [75] Inventor: Hugh Willmott Grenfell, Swansea, Glamorgan, Wales [73] Assignee: The Steel Company of Wales Limited, Glamorgan, Wales [22] Filed: Dec. 4, 1970 21 Appl. No.: 95,339

Related US. Application Data [62] Division of Ser. No. 818,299, April 22, 1969, Pat.

' [52] U.S. Cl. ..164/281, 164/46, 164/276, 164/48, 118/636, 118/621, 118/93.4, 118/9343 [51] Int. Cl. ..B22d 11/10 [58] Field of Search ..1 18/621, 127, 636;

[56] References Cited UNITED STATES PATENTS Lloyd 164/276 X Apr. 17, 1973 521,791 6/1894 Griscom 164/276 3,344,843 10/1967 Miller .164/46 X 2,639,490 5/1953 Brennan 164/278 X 2,864,137 12/1958 Brennan ..164/46 305,716 9/1884 Schulze-Berge ..l64/277 X 2,491,889 12/1949 Bennett et a1. ..1 18/636 X Primary Examiner-11. Spencer Overholser Assistant ExaminerV. K. Rising Attornay-Buell, Blenko & Ziesenheim 57 ABSTRACT The present invention relates to a process for the continuous casting of metal strip, which process comprises imparting an electrostatic charge of at least 80,000 volts to a stream of molten metal, passing the stream of metal through a nozzle into an inert atmosphere and allowing the stream leaving the nozzle to atomise to a fine spray, collecting the spray droplets on a cool receiving surface to form a layer of metal on said surface and continuously stripping the layer of metal from said surface.

4 Claims, 1 Drawing Figure FORMATION OF STEEL STRIP This application is a division of co-pending application Ser. No. 818,299, filed Apr. 22, 1969, now U.S. Pat. No. 3,576,207.

The present invention relates to the formation of steel strip.

At the present time steel strip is formed from ingots by slabbing and hot rolling. The present process is to some extent wasteful since in the formation of slabs from ingots, a certain amount of wastage results due to cropping of the ends of the ingot after it is rolled into a slab. These cropped ends have to be severed from the slab and are scrapped. There is also a large loss in yield due to scaling of the ingot and slab in the various stages of the known process.

According to the present invention there is provided a process for the continuous casting of metal strip, which process comprises imparting an electrostatic charge of at least 80,000 volts to a stream of molten metal, passing the stream of metal through a nozzle into an inert atmosphere and allowing the stream leaving the nozzle to atomise to a fine spray, collecting the spray droplets on a cool receiving surface to form a layer of metal on said surface and continuously stripping the layer of metal from said surface.

The receiving surface may be the cylindrical surface of a water-cooled roll and the receiving surface may be earthed. The inert atmosphere may be any gas which will not react with or dissolve to an appreciable extent in steel under the. particular process conditions and which does not adversely affect the quality of the steel but is preferably argon, crypton or other inert gas.

Thestream of molten steel may be tapped from a ladle or tundish which is insulated from its surroundings, the melt contained therein contacting with an electrode charged to a potential of at least 80,000 volts and preferably 100,000 to 200,000 volts to impart a charge to the contents of the tundish and to a stream of molten steel leaving the same.

The layer of steel stripped from the collecting surface may subsequently be rolled to form strip of the desired thickness.

Following is a description by way of example and with reference to the accompanying drawing of one i method of carrying the invention into effect.

The accompanying drawing is a diagrammatic side view partially in section of apparatus for use in the process of the present invention.

A tundish 10 is provided with a discharge opening including a downwardly extending nozzle 13. A tapping rod 11 is vertically disposed with respect to the bottom 12 of the tundish l and extending therethrough to terminate at a lower end which is adapted to close the discharge opening. The tapping rod is provided with control means for controlling the flow of molten steel passing from the tundish l0 and through the nozzle 13. The nozzle end 13 of the tapping rod 11 is disposed within a collecting chamber 15 having an inert atmosphere of, for instance, argon which is maintained in the collecting chamber under a pressure slightly greater than atmospheric. Immediately below the nozzle 13 is disposed a rotatable water-cooled roll 16 which is disposed within the bottom surface 17 of the collecting In operation, the tundish is periodically charged with molten steel and an electrode 20 is inserted in the molten steel and maintained at a potential of 100,000 volts. The tundish l0 and collecting chamber 15 are substantially insulated from their surroundings and the tapping rod 11 is operated to allow a continuous controlled stream of molten steel charged at a potential of 100,000 volts to pass down the tapping rod and out of the bottom end of the nozzle 13 into the collecting chamber 15. Free of the constraint provided by the walls of the conduit 21 in the tapping rod 11, the stream of molten steel debouching from the lower end of the nozzle 13 separates into a finely atomised spray 22 of steel droplets, the atomisation being caused by the electro-static charge on the stream which causes the stream to split into a number of small droplets each containing a lower electrostatic charge.

The roller 16 disposed below the nozzle 13 is earthed by means of conductor 23 and the droplets and the spray are attracted towards the surface 24 of the roll 16 and are deposited thereon to form a thin layer 25 of steel. The droplets coalesce on the cooled surface of the roll to form an uniform layer. The roll 16 is slowly rotated and is continually cooled by water passing through the inner structure of the roll.

The layer 25 of steel so formed is carried by the surface 24 of the roll 16 out of the collecting chamber 15 through the gland 18 between the wall 17 of the collecting chamber 15 and the surface 24 of the roll 16 and at a point externally of the collecting chamber, is stripped from the surface 24 of the roll 16 by suitable stripper means 27. The steel strip 28 so produced is chamber 15 glands 18 being provided to permit rotation of the roll 16 about its axis 19 with respect to the chamber 15 and without substantial loss of argon.

then passed between one or more stands of rollers to a coiler 29 in the usual way. The strip obtained on the coil may be suitably reduced in a reduction mill to a desired thickness.

The sealing glands 18 between the roll 16 and wall 17 may comprise elongate conduits disposed adjacent the roller surface along which a nitrogen or mixture of nitrogen or argon is blown under pressure in an endeavour to prevent or restrict the escape ofargonfrom the collecting chamber. i

It will be appreciated that the process described above can effectively replace the stages of the present process for forming steel strip, from the ladle of steel obtained from the converter, through the ingot stage, soaking pit, slabbing furnaces, and coarse rolls on the hot reduction mill.

Iclaim:

1. Apparatus adapted for continuous casting of metal strip comprising a tundish having a vertically disposed tapping means terminating at its lower end in downwardly extending nozzle means, flow control means positioned adjacent the nozzle means and operable to control the flow of molten metal through said nozzle to the collecting chamber into which said nozzle debouches, rotatable collecting means provided below said nozzle in a surface of the chamber, and electrode means in electrically conductive relationship to the molten metal in the tundish whereby the molten metal is charged and passes from said tundish via said tapping means and nozzle, leaves the end of the nozzle in a downwardly directed spray and is collected on said col lecting means.

2. Apparatus as claimed in claim 1 wherein the collecting means is a rotatable water cooled roll disposed within th bottom wall of the collecting chamber, glands being provided to permit rotation of the roll about its axis with respect to the chamber wall and without substantial loss of gas from the collecting chamber.

3. Apparatus as claimed in claim 1 wherein the tundish and collecting chamber are substantially insulated from their surroundings and wherein motor means are provided for rotation of the roll about its axis so that

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US305716 *Jun 19, 1884Sep 23, 1884 Manufacture of plate-glass
US510808 *Oct 31, 1892Dec 12, 1893 lloyd
US521791 *Jul 24, 1893Jun 26, 1894 Machine for making storage-battery grids of forced lead
US2491889 *Jan 21, 1942Dec 20, 1949Owens Corning Fiberglass CorpProduction of coated glass and the like products
US2639490 *Aug 12, 1948May 26, 1953Brennan Joseph BFormation of metal strip under controlled pressures
US2864137 *Oct 25, 1952Dec 16, 1958Brennan Helen EApparatus and method for producing metal strip
US3344843 *Mar 2, 1965Oct 3, 1967Jorge MillerApparatus for making wrought iron and steel plate
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4114251 *Sep 22, 1975Sep 19, 1978Allegheny Ludlum Industries, Inc.Process for producing elongated metal articles
US4901784 *Mar 29, 1989Feb 20, 1990Olin CorporationGas atomizer for spray casting
US4907639 *Mar 13, 1989Mar 13, 1990Olin CorporationAsymmetrical gas-atomizing device and method for reducing deposite bottom surface porosity
US4917170 *Sep 20, 1988Apr 17, 1990Olin CorporationNon-preheated low thermal conductivity substrate for use in spray-deposited strip production
US4925103 *Mar 13, 1989May 15, 1990Olin CorporationMagnetic field-generating nozzle for atomizing a molten metal stream into a particle spray
US4926927 *Sep 20, 1988May 22, 1990Olin CorporationVertical substrate orientation for gas-atomizing spray-deposition apparatus
US4938278 *Sep 20, 1988Jul 3, 1990Olin CorporationSubstrate for use in spray-deposited strip
US4945973 *Nov 14, 1988Aug 7, 1990Olin CorporationThermal conductivity of substrate material correlated with atomizing gas-produced steady state temperature
US4966224 *Sep 20, 1988Oct 30, 1990Olin CorporationSubstrate orientation in a gas-atomizing spray-depositing apparatus
US4977950 *Mar 13, 1989Dec 18, 1990Olin CorporationEjection nozzle for imposing high angular momentum on molten metal stream for producing particle spray
EP0629459A1 *Jun 17, 1994Dec 21, 1994Kawasaki Steel CorporationMethod and apparatus for producing thin ribbon
Classifications
U.S. Classification164/250.1, 164/427, 118/621, 164/479, 164/48, 118/636, 164/46, 164/415, 164/437
International ClassificationB22D11/06
Cooperative ClassificationB22D11/0611
European ClassificationB22D11/06D