Classifications

• • 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
  • B22D11/16—Controlling or regulating processes or operations
• • 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
  • B22D41/02—Linings
• • 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

Definitions

• the invention relates to the continuous casting of metals, and more particularly the continuous casting of steel, especially in the form of strips thin.
• Liquid steel is traditionally produced in a converter from liquid iron or electric furnace from scrap. Then its composition precise is set in a pocket. Finally, it is cast on a casting machine keep on going.
• the dispatcher constitutes a reserve of liquid metal which makes it possible to maintain a flow feeding the ingot mold to the desired value at all stages of casting, especially at the start and end of bag emptying, as well as during periods when a ladle change takes place. This allows the emptying of several consecutive pockets without interrupting the pouring (pouring in in sequence).
• the distributor serves as a "buffer" container between the pocket and the ingot (s).
• the first cause can to some extent be remedied by covering the distributor and blowing an inert gas such as argon under the cover, so as to make the atmosphere at the start of casting non-oxidizing.
• Non-metallic inclusions formed during filling of the distributor are mainly found in the surface layers of first tonnes of product poured.
• the product is a slab classic thick (around 200mm for example), it can be tolerable to remove these surface layers by grinding the surface of the slab or a few slabs affected by this fault.
• the object of the invention is to provide users of casting metals, especially steel, and in particular thin strip casting, an efficient and economical way to improve appreciably the cleanliness of the first tonnes poured.
• the invention relates to a process for casting products metal on a continuous casting installation with a distributor coated internally with a refractory material, characterized in that fixed metal sheets on the surface of said refractory material, prior to filling of said distributor with the liquid metal to be poured.
• At least part of the said is fixed. sheets before a distributor preheating operation.
• said sheets are fixed after a distributor preheating operation.
• Said sheets preferably have a composition corresponding to that of cast metal.
• the casting installation continuous is an installation for continuous casting of thin strips.
• the invention essentially consists in internally coat the distributor, before the start of casting, with a set of metal sheets avoiding direct contact between the first tonnes of metal spilled into the distributor and the new refractories from the distributor.
• the contacts between the liquid metal and the refractories are thus, essentially, delayed until the sheet melting This occurs preferably at a when the distributor is completely filled, with flows of metal corresponding to a steady flow regime.
• the dispatcher is coated internally by refractory materials based on oxides (lime, magnesia, alumina, mainly silica) present in variable proportions.
• oxides limestone, magnesia, alumina, mainly silica
• the choice of the composition of these refractories is dictated by considerations of refractoriness, chemical compatibility with the steel to be cast and cost. These refractories can be shaped or flowable.
• the refractory of the distributor are subsequently heated by burners to dry them and to give them a high temperature before casting, limiting losses of the liquid metal when it is introduced into the distributor.
• metal sheets are also prepared intended to cover at least most of the interior coating of the distributor.
• These sheets can be fixed separately on the bottom and the walls side of the distributor by means such as nails, staples etc. At least some of them can also be joined together before they are fixed to the refractories of the distributor.
• the sheets are fixed to the of the distributor while they are still cold.
• the distributor is sent to the preheating station, so that the flames of the burners no longer come into direct contact with refractory, but sheets.
• This can result in local sheet metal mergers at level of flame impacts. But these mergers only concern areas limited and do not call into question the essential protective capacities of sheets.
• the sheets will expand: the means must fixing take into account this expansion so as to prevent the sheets do not curl excessively. For example, if you use nails, you can allow cold clearance between the nails and the contours of the orifices made in the sheets to receive them.
• Another variant of the invention consists in installing the sheets in the distributor already preheated, at least for the most part, if we can use sheet fastening devices protected against refractory radiation of the dispatcher.
• the preheating of the sheets is then carried out by burners, or by an induction device which makes it possible to reach the desired temperature, in the range of 1100-1200 ° C, in a few minutes.
• the area surrounding each of the nozzles through which the liquid metal flows during the casting so that the distaff controlling the flow of the liquid metal by said nozzle can play its role.
• the material of the sheets is chosen so that after it has melted, the components it contains do not change the composition of the metal cast way which places it outside the composition limits for products to be flow.
• the sheets have a composition in accordance with that of said products to be poured.
• they are constituted by portions of bands which have been discarded after their casting (if one is in the case of a installation of thin strip casting) or their rolling, for example heads and coil tails.
• the thickness of the sheets is preferably chosen so that their fusion does not end until the distributor has been filled, and preferably after the start of casting, so at a time when the flows inside the dispatcher have reached their normal regime. At this time, a direct contact generalized between the molten liquid metal and the refractories is possible without cause excessive pollution of the metal. Indeed, inclusions from first metal-refractory reactions will be distributed in a metal flow in continuous flow, instead of concentrating in the metal used for the first filling the distributor as in the prior practice which the invention aims to improve.
• the invention finds, as has been said, a preferred application for installations for the direct casting of thin strips, for which, in general, distributors are relatively small, so with a surface area ratio of refractories / high enclosed metal volume.
• Steel casting is a prime example of application of the invention, but it goes without saying that this can be used for continuous casting of other metals and alloys.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Continuous Casting (AREA)
• Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
• Laminated Bodies (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=29559180

Family Applications (1)

Country Status (7)

Cited By (1)

Citations (6)

• 2002
  • 2002-06-14 FR FR0207384A patent/FR2840828B1/fr not_active Expired - Fee Related
• 2003
  • 2003-06-12 AU AU2003204668A patent/AU2003204668A1/en not_active Abandoned
  • 2003-06-13 BR BR0302070-3A patent/BR0302070A/pt not_active Application Discontinuation
  • 2003-06-13 JP JP2003169245A patent/JP2004034156A/ja not_active Withdrawn
  • 2003-06-13 EP EP03291435A patent/EP1371433A1/de not_active Withdrawn
  • 2003-06-13 US US10/460,676 patent/US20040011500A1/en not_active Abandoned
  • 2003-06-13 KR KR10-2003-0038203A patent/KR20030096078A/ko not_active Application Discontinuation

Patent Citations (6)

Non-Patent Citations (1)

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