EP0897770A1 - Verfahren zum Erwärmen von geschmolzenem Metall in einem Zwischengefäss unter Verwendung eines Plasmabrenners und Zwischengefäss zur Durchführung des Verfahrens - Google Patents

Verfahren zum Erwärmen von geschmolzenem Metall in einem Zwischengefäss unter Verwendung eines Plasmabrenners und Zwischengefäss zur Durchführung des Verfahrens Download PDF

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Publication number
EP0897770A1
EP0897770A1 EP98402012A EP98402012A EP0897770A1 EP 0897770 A1 EP0897770 A1 EP 0897770A1 EP 98402012 A EP98402012 A EP 98402012A EP 98402012 A EP98402012 A EP 98402012A EP 0897770 A1 EP0897770 A1 EP 0897770A1
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EP
European Patent Office
Prior art keywords
compartment
distributor
liquid metal
metal
torch
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP98402012A
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English (en)
French (fr)
Inventor
Michel Henryon
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sollac SA
Original Assignee
Sollac SA
Lorraine de Laminage Continu SA SOLLAC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sollac SA, Lorraine de Laminage Continu SA SOLLAC filed Critical Sollac SA
Publication of EP0897770A1 publication Critical patent/EP0897770A1/de
Withdrawn legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
    • B22D41/005—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like with heating or cooling means
    • B22D41/01—Heating means
    • B22D41/015—Heating means with external heating, i.e. the heat source not being a part of the ladle
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/10—Supplying or treating molten metal
    • B22D11/11—Treating the molten metal

Definitions

  • the invention relates to the field of continuous casting of metals, such as steel. It relates more precisely to continuous casting machines which include a torch plasma to heat the metal during its stay in the distributor.
  • the liquid steel contained in the casting does not flow directly into the bottomless ingot molds with cooled walls where it begins to solidify. It passes first in a container called “distributor", internally coated with refractories, the there are multiple functions.
  • the bottom of the distributor is provided with one or generally several orifices, called “nozzles”, each overhanging an ingot mold, which allows it to distribute the liquid metal in the various ingot molds while the ladle has only one metal flow hole.
  • the distributor constitutes a metal reserve which allows, when a pocket is emptied, to continue pouring the metal during the evacuation of the empty bag and the positioning, then opening, a new pocket. Several pockets can thus be flowed without interruption successive (operation known as "casting in sequence").
  • the dispatcher constitutes a site preferred for settling undesirable non-metallic inclusions present in liquid steel, the more so as the average residence time of the metal is higher.
  • low overheating allows to shorten the duration of solidification of the product: we can take advantage of this to pour the produced at a higher speed, resulting in a productivity gain in the steelworks, or for build a relatively compact continuous casting machine, saving on investments to put into play.
  • a first mode of supply of thermal energy to the metal passing through the distributor consists of scrolling at least part of said metal inside a channel surrounded by an inductor with appropriate characteristics, the currents induced in the metal causing it to heat up by the Joule effect.
  • This solution is quite expensive, and the size of the inductor makes it difficult to apply to small installations size, or which were not originally designed to be equipped with it.
  • WO 95/32069 describes a distributor thus equipped.
  • gas plasmagen such as nitrogen or argon
  • the gas is thus partially ionized and is brought to very high temperature (4000 to 15000 K). It has a thermal conductivity and a power of very high radiation, which makes it suitable for achieving rapid heat transfers and intense with the material to be heated.
  • the cathode and the anode are both integrated into the torch.
  • the cathode is integrated into the torch, and the anode is constituted by the liquid metal to be heated.
  • the sole of the distributor contains a electrically conductive element which is brought into contact with liquid metal during casting and connected to the positive terminal of the torch power supply. he is also possible to provide opposite polarities from those previously specified.
  • the area of the distributor in which the torch is installed must be covered by an internally coated refractory cover.
  • This cover under which we can inject a neutral gas such as argon in addition to the plasma gas (or in its place for periods when the torch is not used), allows to keep in the vicinity of the torch an almost oxygen-free atmosphere, therefore non-polluting for the metal liquid. It also prevents the radiation from the arc from blinding personnel working on the installation.
  • the torch acts on metal naked liquid, therefore not covered by the heat-insulating powder which it is usual to spread on its surface to protect it from atmospheric reoxidation and stop its radiation.
  • the refractors lining the distributor receive a significant part of the radiation from the arc emitted by the torch, and their surface is therefore brought to very high temperatures which can be higher than 1800 ° C when the torch is used at high power. At these temperatures, magnesia or alumina, which are the materials usually used, reaches its melting point, and the coatings deteriorate rapidly. In addition, the refractory which has become liquid tends to flow on the surface of the metal bath, where it forms an insulating crust which hinders heat transfers between the plasma and metal, and may even end up defusing the arc (in the case of a transferred plasma torch). We are therefore forced to find an operating point of the torch which achieves a compromise between sufficient heating of the metal and a tolerable deterioration in refractories, to the detriment of the reheating efficiency that could theoretically offer the torch.
  • the object of the invention is to propose an economical means for limiting the deterioration of the refractory lining of the distributor in the area of action of the torch to plasma, without compromising the efficiency of metal heating by this same torch, or even by increasing it.
  • the invention relates to a process for reheating a liquid metal in a continuous casting distributor by means of a plasma torch located in said distributor, characterized in that said liquid metal flows along the walls internal of a heating compartment arranged inside said distributor, the end of said plasma torch being positioned above the level of the liquid metal contained in said compartment so that the electric arc generated by said plasma torch radiates on the liquid metal flowing along said walls of said compartment.
  • the subject of the invention is also a distributor of continuous metal casting liquid of the type comprising a plasma torch for reheating the liquid metal, a cover crossed by said torch and pouring nozzles formed in the bottom of the distributor, characterized in that it comprises at least one heating compartment in refractory material positioned below said plasma torch, means for supplying said heating compartment with liquid metal by flowing said metal the along the internal walls of said compartment, and means for bringing the liquid metal warmed up to the pouring nozzles.
  • the invention consists in creating a blade of liquid metal along internal walls of the liquid metal heating compartment by the plasma torch.
  • This blade of liquid metal flowing along the walls has the advantage of protecting the refractory constituting said reheating compartment against radiation from the arc electric torch.
  • the refractory thus protected does not undergo radiation direct from the arc and cannot be brought to its melting temperature.
  • the refractory has a longer lifespan, on the other hand the liquid metal contained in the compartment reheating is not polluted by any drips of molten refractory material.
  • Another advantage of the invention is that the direct radiation of the arc on the liquid metal flowing along the walls of the heating compartment increases the thermal efficiency of the plasma torch, since practically all the fractions of the liquid metal passing through the distributor scroll past the arc of the torch which shines directly on them.
  • FIGS. 1a and 1b show a distributor 1 of continuous metal casting according to prior art.
  • a continuous casting machine (not shown) equipped with two ingot molds.
  • he comprises an external metal carcass 2, internally coated with a refractory 3.
  • the interior space of the distributor 1 has a flared shape upwards to allow after the casting easy removal of the refractory lining 1 by simply reversing the distributor 1.
  • the liquid metal 4 (not shown in FIG. 1a) reaches the distributor 1 from a pocket, not shown, and is introduced therein via a tube in refractory 5 connected to the outlet orifice of the pocket. This tube 5 protects the liquid metal 4 which crosses it, against atmospheric reoxidation.
  • nozzles 6, 6 ' Emptying the liquid metal 4 in the molds not shown is carried out by nozzles 6, 6 '.
  • Tubes in refractory 7 connected to the nozzles 6, 6 ' protect the liquid metal 4 against atmospheric reoxidation during its journey between the distributor 1 and the ingot mold which corresponds to each nozzle 6, 6 '.
  • the example of distributor 1 shown is generally rectangular in shape and is internally divided into four compartments by refractory partitions 8, 9, 10.
  • Two partitions 8, 9 are oriented perpendicular to the long sides of the distributor 1; the partition 10 is oriented parallel to the long sides of the distributor and connects the other two partitions 8, 9.
  • the partitions 8, 9, 10 first delimit a first compartment 11 of arrival liquid metal 4, into which the tube 5 connected to the bag opens. Liquid metal 4 then passes through the partition 10 which, for this purpose, is crossed by a pipe 12, and enters thus in a second compartment 13 which, in the example shown, constitutes a lateral protuberance of the distributor 1 located opposite the tube 5 for the arrival of the liquid metal 4.
  • the liquid metal reheating device 4 comprises a plasma torch 18 of a type known in itself. Schematically, it comprises a cathode 19 in one material such as thoriated tungsten, connected to the negative pole of the generator supplying the torch, and surrounded by a metallic envelope 20, for example made of copper, which can play the role of anode.
  • the metal casing 20 only behaves as an anode when striking the arc; but if the torch is of the blown plasma type, this metal casing 20 is constantly connected to the positive pole of the generator supplying the torch.
  • anode 22 is installed, for example, by a steel bar cooled over at least part of its length, and connected to the positive pole of the generator supplying the torch. Between cathode 19 and metal liquid 4 which is in contact with anode 22 therefore creates an electric arc 23 through which passes plasma gas, so as to heat the liquid steel 4 present in the second compartment 13, which will be called "heating compartment".
  • a cover 24 (not shown in FIG. 1a), coated on the inside a refractory layer 25, through which the torch 18 passes.
  • this cover 24 allows to confine the atmosphere surrounding the heating compartment 13 by putting it at sheltered from the outside atmosphere and allowing to keep above the liquid metal 4 argon injected by the torch 18. This eliminates atmospheric reoxidation which, without that would inevitably happen, especially since in this warming compartment 13, it is not possible to cover the surface of the liquid metal 4 with an insulating powder which interfere with thermal and electrical transfers between the torch 18 and the metal 4.
  • Such a powder 26 is present on the surface of the liquid metal 4 in the other compartments 11, 14, 15 of the dispatcher. At least during the periods when the torch 18 is not used, it is possible to also inject argon under the cover 24 through an orifice 27.
  • the radiation of the arc electric 23 causes rapid wear of the emerged part of the refractory 3 covering the distributor 1 in the heating compartment 13. This wear may eventually until its superficial fusion, with all the problems previously mentioned that it drives. It would therefore be necessary to carry out all of the refractories exposed to the arc 23 in one material with very high resistance to radiation, which would cause additional costs hardly acceptable.
  • the distributor according to the invention shown in Figures 2a and 2b is a improvement of the previous distributor (their common elements are designated by same references in FIGS. 1 and 2), in which the above problem is solved by economically.
  • the heating compartment 13 has a channel peripheral 30 formed on the upper edge of said reheating compartment 13 and completely surrounding said compartment 13.
  • the liquid metal 4 contained in the inlet compartment 11 passes through the partition 10 separating the two compartments by a pipe 33 passing through said partition 10.
  • This pipe 33 passes through partition 10 just below the level of the insulating powder layer 26 covering the surface of the liquid metal 4 and protecting it from atmospheric oxidation in the metal inlet compartment liquid 11, and it emerges at the level of the channel 30 of the heating compartment 13.
  • the liquid metal 4 is thus distributed peripherally in the channel 30 around the reheating compartment 13.
  • the inlet compartment 11 is supplied with a flow of liquid metal 4 sufficient to cause said metal 4 therein to extend beyond the channel 30.
  • the flow of said liquid metal 4 along the internal walls of the compartment reheating 13 is thus uniformly ensured by this overflow.
  • the thickness of the sheet of liquid metal 4 flowing along the internal walls of the compartment reheating 13 is optimally of the order of 1 to 2 mm to ensure both good protection of the refractories 3 against the radiation of the arc 23 and a good efficiency of the Thermal transfer.
  • the heating compartment 13 has a diameter of approximately 0.6 m and if the liquid metal 4 travels there at the rate of 2.4 rpm with an initial temperature of 1550 ° C., can expect an increase in temperature of the liquid metal 4 which can reach around 20 ° C with the usual plasma torches.
  • a deflector 32 of refractory material is preferably fixed on said cover 24, and surrounds said plasma torch 18.
  • the distributor 1 according to the invention shown in Figures 3a and 3b constitutes a second example of implementation of the invention.
  • the nose of the plasma torch 18 enters the cylinder 31 at a distance of approximately 0.2 m from the level of the liquid metal 4 contained in said cylinder 31. Its upper end is located at a level just below the level nominal liquid metal 4, and is positioned just below the plasma torch 18.
  • the liquid metal 4 contained in the receiving compartment 11 of said liquid metal 4 enters the reheating compartment 13 by overflow and flows along the internal walls of the cylinder 31 constituting said heating compartment 13.
  • the liquid metal 4 passes into the casting compartments 14, 15 by borrowing pipes 37, 38 which connect them to the heating compartment 13. They rest on the bottom of the receiving compartment 11 and pass through the partitions 8, 9
  • the surface of the liquid metal 4 located in the receiving compartment 11 is covered with a layer of insulating powder 26 intended to protect said liquid metal 4 from atmospheric oxidation. However, this insulating powder 26 would hinder the heat transfers and electric between the plasma torch 18 and said liquid metal 4.
  • a barrier 36 intended to retaining said insulating powder 26 crosswise crosses the upper part of the receiving compartment 11, on the path of the liquid metal 4 towards the compartment of heating 13. This dam 36 is constituted by a plate of refractory material.
  • a removable deflector 32 in refractory material is preferably fixed on the cover 24 of refractory material and surrounds the plasma torch 18.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
  • Furnace Details (AREA)
EP98402012A 1997-08-11 1998-08-06 Verfahren zum Erwärmen von geschmolzenem Metall in einem Zwischengefäss unter Verwendung eines Plasmabrenners und Zwischengefäss zur Durchführung des Verfahrens Withdrawn EP0897770A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9710307A FR2767081B1 (fr) 1997-08-11 1997-08-11 Procede de rechauffage d'un metal liquide dans un repartiteur de coulee continue au moyen d'une torche a plasma, et repartiteur pour sa mise en oeuvre
FR9710307 1997-08-11

Publications (1)

Publication Number Publication Date
EP0897770A1 true EP0897770A1 (de) 1999-02-24

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EP98402012A Withdrawn EP0897770A1 (de) 1997-08-11 1998-08-06 Verfahren zum Erwärmen von geschmolzenem Metall in einem Zwischengefäss unter Verwendung eines Plasmabrenners und Zwischengefäss zur Durchführung des Verfahrens

Country Status (5)

Country Link
US (1) US5963579A (de)
EP (1) EP0897770A1 (de)
BR (1) BR9803140A (de)
CA (1) CA2243523A1 (de)
FR (1) FR2767081B1 (de)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SG87016A1 (en) * 1999-02-02 2002-03-19 Singapore Polytechnic Metal casting
TW469757B (en) * 1999-12-13 2001-12-21 Nippon Steel Corp A transferred plasma heating anode
IL140246A (en) * 2000-12-12 2007-09-20 Pavel Dvoskin Treatment of molten metals by moving an electric arc during aggregation
IL144422A0 (en) * 2001-07-18 2002-05-23 Netanya Plasmatec Ltd Riser(s) size reduction and/or metal quality improving in gravity casting of shaped products by moving electric arc
IL145099A0 (en) * 2001-08-23 2002-06-30 Netanya Plasmatec Ltd Method and apparatus for stirring and treating continuous and semi continuous metal casting
US20080136069A1 (en) * 2004-10-21 2008-06-12 Micropyretics Heaters International, Inc. Air plasma induced low metal loss
DE102013200062A1 (de) * 2013-01-04 2014-07-10 Ford-Werke Gmbh Vorrichtung zum thermischen Beschichten einer Oberfläche
US11235389B2 (en) * 2018-09-19 2022-02-01 Molyworks Materials Corp. Deployable manufacturing center (DMC) system and process for manufacturing metal parts
CN109648068B (zh) * 2019-01-29 2024-06-21 大冶特殊钢有限公司 一种感应加热中间包流钢通道及其防护方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59110741A (ja) * 1982-12-17 1984-06-26 Nippon Steel Corp プラズマア−ク加熱における着火方法
JPH03138052A (ja) * 1989-10-23 1991-06-12 Nkk Corp 加熱装置付きのタンディッシュ
EP0453188A2 (de) * 1990-04-19 1991-10-23 The BOC Group plc Plasmabeheizung einer Tundisher
JPH03285745A (ja) * 1990-03-30 1991-12-16 Nkk Corp 鋼の連続鋳造方法及び装置
WO1995032069A1 (fr) * 1994-05-24 1995-11-30 Societe Des Terres Refractaires Du Boulonnais Dispositif de guidage de l'acier en fusion dans un repartiteur

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5272718A (en) * 1990-04-09 1993-12-21 Leybold Aktiengesellschaft Method and apparatus for forming a stream of molten material
US5226949A (en) * 1992-07-30 1993-07-13 Retech, Inc. Method and apparatus for removal of floating impurities on liquid
US5785923A (en) * 1996-03-08 1998-07-28 Battelle Memorial Institute Apparatus for continuous feed material melting

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59110741A (ja) * 1982-12-17 1984-06-26 Nippon Steel Corp プラズマア−ク加熱における着火方法
JPH03138052A (ja) * 1989-10-23 1991-06-12 Nkk Corp 加熱装置付きのタンディッシュ
JPH03285745A (ja) * 1990-03-30 1991-12-16 Nkk Corp 鋼の連続鋳造方法及び装置
EP0453188A2 (de) * 1990-04-19 1991-10-23 The BOC Group plc Plasmabeheizung einer Tundisher
WO1995032069A1 (fr) * 1994-05-24 1995-11-30 Societe Des Terres Refractaires Du Boulonnais Dispositif de guidage de l'acier en fusion dans un repartiteur

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 008, no. 225 (C - 247) 16 October 1984 (1984-10-16) *
PATENT ABSTRACTS OF JAPAN vol. 015, no. 354 (M - 1155) 6 September 1991 (1991-09-06) *
PATENT ABSTRACTS OF JAPAN vol. 016, no. 119 (M - 1225) 25 March 1992 (1992-03-25) *

Also Published As

Publication number Publication date
FR2767081B1 (fr) 1999-09-17
US5963579A (en) 1999-10-05
CA2243523A1 (fr) 1999-02-11
BR9803140A (pt) 1999-10-13
FR2767081A1 (fr) 1999-02-12

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