Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
  • B21B1/46—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting
  • B21B1/463—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting in a continuous process, i.e. the cast not being cut before rolling
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
  • B21B45/02—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for lubricating, cooling, or cleaning
  • B21B45/0239—Lubricating
  • B21B45/0245—Lubricating devices
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B9/00—Measures for carrying out rolling operations under special conditions, e.g. in vacuum or inert atmosphere to prevent oxidation of work; Special measures for removing fumes from rolling mills
• • 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
  • B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
• • 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
  • B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
  • B22D11/0637—Accessories therefor
  • B22D11/0665—Accessories therefor for treating the casting surfaces, e.g. calibrating, cleaning, dressing, preheating
  • B22D11/0668—Accessories therefor for treating the casting surfaces, e.g. calibrating, cleaning, dressing, preheating for dressing, coating or lubricating
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
  • B21B45/02—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for lubricating, cooling, or cleaning
  • B21B45/0239—Lubricating
  • B21B45/0242—Lubricants
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
  • B21B45/02—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for lubricating, cooling, or cleaning
  • B21B45/0239—Lubricating
  • B21B45/0245—Lubricating devices
  • B21B45/0263—Lubricating devices using solid lubricants
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
  • Y02P70/10—Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working

Definitions

• the invention relates to the continuous casting of metals. It relates more precisely to the continuous casting of metal strips of narrow thickness directly from a liquid metal using the twin roll casting method or generally between cooled, moving walls.
• the twin roll casting method consists of casting a metal strip, in carbon steel for example or stainless steel, Fe—Ni or Fe—Si alloy or other ferrous or non-ferrous alloys, through the solidification of liquid metal on the cylindrical side walls of two rolls rotating in opposite directions and cooled in the inside. Two solidified “skins” are formed on these walls and they are caused to be joined substantially at the “neck” i.e. the point where the space between the walls is narrowest and substantially equal to the thickness of the strip it is desired to cast (in the order of 1 to 10 mm, generally 3 to 5 mm).
• the solidified strip leaving the casting rolls then undergoes hot rolling in one or more steps in one or more rolling stands arranged in line with the casting rolls. It is only after this hot rolling (and optionally other metallurgical operations such as reheating and/or controlled cooling) that the strip is wound in a reel and shipped to the customer or to other processing stations such as a cold rolling line.
• In-line hot rolling makes it possible to obtain spooled, thin strips of steel (and iron alloys in general) having a thickness close to the desired end thickness of the product without having to achieve this narrow thickness directly on leaving the casting rolls (where thicknesses of less than approximately 3 mm are difficult to achieve). It also makes it possible to refine and homogenize the microstructure of the strip.
• the rate of reduction during hot rolling should be as high as possible.
• the purpose of the invention is to propose a method and an installation for the continuous casting of thin strips, which gives access under advantageous economic conditions to very high reduction rates during in-line hot rolling.
• the subject of the invention is a method for the continuous direct casting of a metal strip, according to which said strip is cast by solidification of liquid metal in an ingot mould with cooled moving walls and said strip is then given in-line hot rolling, characterized in that a product is applied to the surface of the strip as it leaves the ingot mould which leaves a lubricant layer on said surface which subsists for hot rolling of the strip and causes a gaseous release contributing towards protection of said surface from oxidation.
• Said lubricant layer may be in a carbonaceous material.
• Said product leaving a lubricant layer to subsist may then be graphite.
• Said product leaving a lubricant layer to subsist may be a grease containing calcium carbonate.
• Said product leaving a lubricant layer may be acetylene.
• Hot rolling may be conducted with a reduction rate of at least 50%.
• Said liquid metal may be a ferrous alloy.
• a further subject of the invention is a plant for continuous direct casting of a thin metal strip, of the type comprising an ingot mould with cooled, moving walls where solidification of said strip occurs and an in-line hot rolling unit for said solidified strip, characterized in that it comprises means for applying a product to the surface of said strip as it leaves the ingot mould, which leaves a lubricant layer subsisting on said surface as it enters the hot rolling unit.
• Said moving walls may be the side walls of two rolls rotating in opposite directions.
• Said moving walls may be two moving belts.
• the plant may comprise an inertization chamber for said strip between its exit from the ingot mould and its entry into the hot rolling unit.
• the invention consists of applying a product to the surface of the strip as it leaves the casting rolls (product initially in a solid, liquid or gaseous state) which leaves a lubricant layer subsisting on the surface of the strip up until the time the strip enters the hot rolling mill.
• the lubricant effect during this hot rolling makes it possible to achieve reduction rates of 50% or more in a single pass.
• the obtaining of these very high reduction rates under satisfactory conditions of strip surface quality can only be contemplated if the surface of said strip is free or almost free from carbon deposit at the time it is rolled. From this viewpoint the invention is also particularly advantageous.
• the layer of product intended to form the lubricant acts as a protective layer against atmospheric oxidation.
• cracking of the product at the time it is applied to the strip and in the instants following thereafter results in the formation of gases which act to make the strip surface inert by drastically reducing the surrounding oxygen concentration. If an inertization chamber is used, these gases will remain therein and themselves take part in surface inerting, which makes it possible to reduce the added quantities of neutral or reducing gas. In the most favourable cases, it is even possible to eliminate the inertization chamber, the release of gases derived from the product on heating and decomposed by the heat of the strip surface proving sufficient to ensure the desired low oxygen concentration in the vicinity of the strip surface.
• the strip leaving the casting rolls takes a few seconds to arrive at the in-line hot rolling unit and has a temperature in the region of 950 to 1050° C.
• the characteristics of the applied product must therefore be such that it is able to subsist in effective form, for example in the form of a carbonaceous material on the surface of the strip as it enters the hot rolling unit, and is able to produce protective gases, due to its cracking, at least during the instants after the time the strip leaves the casting rolls. It is during these instants that the strip is hottest and hence the risk of carbon deposit is highest. If no inertization chamber is used, it is preferable for this cracking to be continued as far as the hot rolling unit.
• the type of product and the quantity applied to each surface of the strip must be chosen accordingly.
• graphite powder may be cited or a grease containing up to 50% calcium carbonate.
• this latter type of product may be particularly suited for coating the strip, in particular over the portions of its travel during which it is vertical or on its passive surface as it enters the rolling machine.
• This carbonaceous residue may, for example, consist of blowing acetylene onto the strip surface. Its combustion according to the reaction: 2C 2 H 2 +2O 2 ⁇ 2C+H 2 O+CO+CO 2 +H 2 produces graphite which then constitutes the lubricant layer which the invention is intended to obtain. This reaction also produces hydrogen which causes the atmosphere to be a reducing atmosphere.
• the invention has been described under its application to the casting of thin metal strips between twin rolls. But is also possible to consider its application to other types of thin strip casting installations, for example to the casting of thin strips of relatively wide thickness, in the order of 5 to 10 mm, between two cooled, moving belts.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Metal Rolling (AREA)
• Continuous Casting (AREA)
• Treatment Of Steel In Its Molten State (AREA)
• Lubricants (AREA)
• Heat Treatment Of Strip Materials And Filament Materials (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=33484305

Family Applications (1)

Country Status (19)

Cited By (1)

Citations (14)

Family Cites Families (10)

• 2003
  • 2003-06-10 FR FR0306943A patent/FR2855992B1/fr not_active Expired - Fee Related
• 2004
  • 2004-06-08 JP JP2006516267A patent/JP4474412B2/ja not_active Expired - Lifetime
  • 2004-06-08 DK DK04767286T patent/DK1631405T3/da active
  • 2004-06-08 ES ES04767286T patent/ES2281003T3/es not_active Expired - Lifetime
  • 2004-06-08 EP EP04767286A patent/EP1631405B1/fr not_active Expired - Lifetime
  • 2004-06-08 BR BRPI0411264-4A patent/BRPI0411264A/pt not_active Application Discontinuation
  • 2004-06-08 AT AT04767286T patent/ATE353723T1/de active
  • 2004-06-08 DE DE602004004779T patent/DE602004004779T2/de not_active Expired - Lifetime
  • 2004-06-08 WO PCT/FR2004/001420 patent/WO2004110678A1/fr active IP Right Grant
  • 2004-06-08 CA CA002527601A patent/CA2527601A1/fr not_active Abandoned
  • 2004-06-08 RU RU2005141425/02A patent/RU2311988C2/ru not_active IP Right Cessation
  • 2004-06-08 MX MXPA05012989A patent/MXPA05012989A/es active IP Right Grant
  • 2004-06-08 KR KR1020057021401A patent/KR101064608B1/ko not_active IP Right Cessation
  • 2004-06-08 PL PL04767286T patent/PL1631405T3/pl unknown
  • 2004-06-08 CN CNB2004800159718A patent/CN100349670C/zh not_active Expired - Fee Related
  • 2004-06-08 SI SI200430235T patent/SI1631405T1/sl unknown
  • 2004-06-08 US US10/559,808 patent/US20060169373A1/en not_active Abandoned
  • 2004-08-06 UA UAA200600156A patent/UA81049C2/uk unknown
• 2005
  • 2005-11-09 ZA ZA200509050A patent/ZA200509050B/en unknown

Patent Citations (14)

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