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
  • B22D11/06—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
  • B22D11/0622—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars formed by two casting wheels
• • 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
  • B22D11/064—Accessories therefor for supplying molten metal
• • 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
  • B22D11/12—Accessories for subsequent treating or working cast stock in situ
• • 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
  • B22D41/14—Closures

Definitions

• the invention relates to a method and a device for obtaining a thin metal strip having a controlled and constant thickness profile by continuous casting between movable molds, for example between blocks, between ribbons, between blocks and ribbons or preferably between cooled rolls. It mainly concerns aluminum and its alloys.
• Continuous casting installations between mobile molds generally include an oven supplying liquid metal, using a chute, an injection device uniformly distributing said liquid metal in the air gap located between the mobile molds.
• This device comprises at least one injector having a downstream end of the width of the strip to be cast and the lips of which have a shape adapted to that of the molds; in general it also includes an injector tank located upstream of said injector.
• the transformation tools give a tolerance in absolute value which, in the case of a thin strip, corresponds to an increase in the tolerance in relative value; however, the objective is to obtain the lowest possible relative tolerance, this therefore implies maintaining the absolute tolerance within limits which are all the more strict as the thickness of the thin strip is low.
• the relative tolerance to be obtained on the crown of a strip is generally ⁇ 0.2%, which translates to a strip of thickness of 5mm having a crown of 0.7%, that is to say 35 ⁇ m, by a tolerance ( ⁇ 0.2%) of ⁇ 10 ⁇ m, while for a 2.5mm thick strip having a convex of 07%, i.e. 17.5 ⁇ m, the tolerance of ⁇ 0.2% becomes ⁇ 5 ⁇ m more difficult to hold.
• the thickness of the strip is given by the dimension of the air gap resulting mainly from the forces exerted by the cylinders on the metal being solidified and solidified and by the speed of casting.
• the prerequisite for obtaining a constant thickness is to have a uniform stream of liquid metal in speed and temperature in the injection device so as to obtain a solidification front as uniform as possible in the air gap.
• This uniformity is achieved using known actuators such as the forces exerted by the rolls on the metal, the casting speed, the lubrication or the cooling of the rolls, as is well known in rolling. This is for example described in US patents 4,550,767 (Alcoa), 4,751,958 (Hunter), 5,452,827 (Eckert).
• the usual means used to obtain it consist in acting on the distribution of the forces applied to the metal by the cylinders, to be modulated cooling the cylinders to modify their convexity and / or to adapt the lubrication applied during casting.
• patents EP 0407978 Hunter
• US 4944342 Liauener
• patent EP 0228038 Alcoa
• patent WO 95/23602 Davy Me ee
• patent EP 0081848 Hazelet
• action is taken on the solid metal or in the course of solidification to control the thickness profile of the strip.
• the Applicant has sought to improve the regularity and the control of the thickness profile by simple means making it possible to replace, or to supplement, the usual means, said thickness profile having to remain within the tolerances requested by the subsequent processor. which are all the more difficult to comply with as the strip is thin.
• the invention is a process for continuous casting between movable molds of a metal strip comprising a supply of liquid metal to an injection device comprising at least one injector, and optionally an injector tank located upstream of said injector, said liquid metal distributed by the ⁇ v ⁇ le end of said injector in the gap of the movable molds, characterized in that the solidification front of the liquid metal is deformed between the movable molds to obtain the desired strip thickness profile.
• the solidification front of the liquid metal represents the interface separating the liquid phase from the solid phase and is located in the air gap.
• the Applicant has thus sought to act only on the liquid metal to supplement, or replace, the usual means of controlling the regularity of the thickness profile while the usual means, as has already been said, were not interested than solid metal or solidification.
• the invention therefore consists in imposing a speed distribution and a thermal profile at the outlet of the liquid metal injection device such that the deformation of the solidification front obtained is adapted to the profile of strip thickness sought.
• the injection device may include an injector tank, located upstream and integral with the injector, the function of which is to ensure a first distribution of the liquid metal, that of the injector being complete this distribution and bring the liquid metal into the air gap.
• the injector tank receiving the liquid metal generally comprises a bottom and two side walls.
• the injector generally comprises a bottom, two side walls and an upper wall facing the bottom; the side walls can be convergent, parallel or divergent; the bottom and the upper wall are generally convergent or parallel. Its downstream end is profiled to introduce the liquid metal between the movable molds or the cylinders and distribute it over their entire width.
• At least one of the following means is used.
• At least one mobile baffle generally flat and in one or more elements, can be placed in the injector tank and cross the flow of liquid metal transversely and at least partially; it is advantageous according to the invention that on each side of the baffle there is a space separating it from the side walls of the injector tank. Its width represents between 40 and 95% of the width of the injector tank.
• the baffle can also be moved around horizontal, vertical or oblique axes but also forward or backward, that is to say parallel to the direction of the flow of liquid metal. Displacement can also combine all these movements.
• each of these can be moved vertically and independently of each other. These simple movements make it possible to modify the thermal and speed profiles of liquid metal veins and thus to deform the solidification front in the desired manner, and this all the better since the baffle leaves a passage at each of its lateral ends. in addition to the underpass, to control the strip thickness profile.
• the injector tank can advantageously be of reduced dimensions compared to the width of the injector.
• At least one orientable deflector preferably profiled like an airplane wing, in the injector between the bottom and the upper face.
• it makes it possible to modify the flow, therefore the thermal path of the liquid metal; but it is preferred to use it in addition to the baffle since its implementation is less easy.
• These means may include a plurality of electrical resistances and / or also a plurality of tubes of heat-transfer fluid and / or refrigerant, liquid or gaseous, distributed over the surface of the injection device or embedded in its walls and supplied individually.
• the invention also relates to a device making it possible to obtain the deformation of the solidification front, that is to say a device for continuous casting between movable molds comprising a supply of liquid metal including at least one injector, optionally an injector tank located upstream of said injector and at least one of the following means:
• a mobile baffle in one or more elements, crossing transversely and at least partially the flow of liquid metal in the injector tank,
• At least one orientable deflector preferably profiled like an airplane wing, in the injector
• the baffle can be fitted at each of its ends with movable flaps allowing the dimensions of the lateral space to be modified.
• the movements of the baffle or one of its elements, and / or the orientation of the baffle or of the deflectors and / or the local temperature adjustment can be automated and controlled according to the faults observed and the characteristics of the liquid metal feed.
• Figure 1 shows a liquid metal supply for carrying out the method according to the invention and comprising a movable baffle; this supply is seen in section in (a) and in plan in (b), when said mobile chicane is in a single element and is seen from the front in (c) when said mobile chicane comprises several vertically adjustable elements.
• FIG. 2 represents an example of the result obtained with the method according to the invention.
• the supply of liquid metal comprises a chute (1) for supplying liquid metal, an injector tank (2) with a baffle (3) movable in several directions, according to the invention, making it possible to deform the solidification front and an injector (4) having profiled outlet lips (5) adapted to the movable molds between which they introduce the liquid metal.
• a space (6) separating it from the edges of the injector tank (2).
• FIG. 2 represents the evolution of the strip thickness profile over time, measured continuously with an X-ray thickness gauge, when the solidification front is deformed by modifying the position of a mobile baffle like that of figure 1.
• BASC tilting
• BOMB bulge

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Continuous Casting (AREA)
• Casting Or Compression Moulding Of Plastics Or The Like (AREA)
• Moulding By Coating Moulds (AREA)
• Moulds For Moulding Plastics Or The Like (AREA)
• Coating Apparatus (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=9524202

Family Applications (1)

Country Status (11)

Families Citing this family (2)

Family Cites Families (13)

• 1998
  • 1998-03-13 FR FR9803332A patent/FR2775916B1/fr not_active Expired - Fee Related
• 1999
  • 1999-03-10 CN CN99803471A patent/CN1096901C/zh not_active Expired - Fee Related
  • 1999-03-10 DE DE69904451T patent/DE69904451T2/de not_active Expired - Fee Related
  • 1999-03-10 WO PCT/FR1999/000527 patent/WO1999047293A1/fr not_active Ceased
  • 1999-03-10 TR TR2000/02640T patent/TR200002640T2/xx unknown
  • 1999-03-10 KR KR1020007010006A patent/KR20010041761A/ko not_active Withdrawn
  • 1999-03-10 AU AU27325/99A patent/AU2732599A/en not_active Abandoned
  • 1999-03-10 BR BR9909259-0A patent/BR9909259A/pt not_active Application Discontinuation
  • 1999-03-10 EP EP99907673A patent/EP1062065B1/de not_active Expired - Lifetime
  • 1999-03-12 AR ARP990101089A patent/AR014717A1/es not_active Application Discontinuation
• 2000
  • 2000-09-12 NO NO20004551A patent/NO20004551D0/no not_active Application Discontinuation

Non-Patent Citations (1)

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