WO2025093902A1 - Procédé de coulée continue d'un produit métallique composite - Google Patents

Procédé de coulée continue d'un produit métallique composite Download PDF

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Publication number
WO2025093902A1
WO2025093902A1 PCT/IB2023/060908 IB2023060908W WO2025093902A1 WO 2025093902 A1 WO2025093902 A1 WO 2025093902A1 IB 2023060908 W IB2023060908 W IB 2023060908W WO 2025093902 A1 WO2025093902 A1 WO 2025093902A1
Authority
WO
WIPO (PCT)
Prior art keywords
continuous casting
mold
flow rate
liquid metal
frini
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.)
Pending
Application number
PCT/IB2023/060908
Other languages
English (en)
Inventor
Paul Naveau
Nicolas PIRLOT
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.)
ArcelorMittal SA
Original Assignee
ArcelorMittal SA
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 ArcelorMittal SA filed Critical ArcelorMittal SA
Priority to PCT/IB2023/060908 priority Critical patent/WO2025093902A1/fr
Publication of WO2025093902A1 publication Critical patent/WO2025093902A1/fr
Anticipated expiration legal-status Critical
Pending legal-status Critical Current

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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
    • B22D11/007—Continuous casting of metals, i.e. casting in indefinite lengths of composite ingots, i.e. two or more molten metals of different compositions being used to integrally cast the ingots
    • 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
    • B22D11/103—Distributing the molten metal, e.g. using runners, floats, distributors
    • 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
    • B22D11/108—Feeding additives, powders, or the like
    • 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
    • B22D11/116—Refining the 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
    • B22D11/16—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
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/16—Controlling or regulating processes or operations
    • B22D11/18—Controlling or regulating processes or operations for pouring
    • 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
    • B22D41/50—Pouring-nozzles
    • 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
    • B22D41/50—Pouring-nozzles
    • B22D41/58—Pouring-nozzles with gas injecting means

Definitions

  • the invention relates to a continuous casting process.
  • the invention relates to a continuous casting process made for manufacturing a composite metallic product.
  • the continuous casting of steel is a well-known process. It consists in pouring a liquid metal from a ladle into a tundish intended to regulate the stream, then pouring the metal into the upper part of a water-cooled bottomless copper mold undergoing a vertical reciprocating movement. The solidified semifinished product is extracted from the lower part of the mold by rollers. The liquid metal is introduced into the mold by means of a tubular duct called a nozzle placed between the tundish and the mold.
  • Japanese Patent Application JP11 197807 describes a continuous casting process for manufacturing a multilayer cast piece, using a nozzle being formed of a vertical duct having multiple discharge ports in the vertical direction, the duct being divided on the inside by a partition wall creating multiple molten steel flow passages and having one or multiple ports for adding raw material.
  • the continuous casting process described consists in injecting two types of molten metals, differing in composition, into the mold at different heights thus creating two pools of liquid metal, an upper pool and a lower pool, differing by their respective composition.
  • the metal located in the upper pool solidifies first, creating a shell having the composition of the upper pool.
  • the metal located in the lower pool solidifies then inside the shell, forming the bulk of the material and having the composition of the lower pool, thus creating a composite metallic product.
  • the stability of the interface between the pools is one of the main parameters that define the quality of the separation between the shell and the bulk of the composite product.
  • Japanese Patent Application JP1 1197807 uses a static magnetic field and injects the different streams of liquid metal above and below the magnetic field.
  • the magnetic field acts as a brake towards the liquid metal thus reducing mixing of the two pools and stabilizing the boundary.
  • the present invention discloses a method of continuous casting for manufacturing a composite metallic product, allowing the casting of a product having a shell and a bulk of different composition with a maximized difference in composition and well defined, thus being of better quality.
  • the object of the invention is a method of continuous casting of a composite metallic product having a distinct shell 16 and bulk 17 of different compositions, said shell 16 having a constant thickness, said method comprising the steps of:
  • A. pouring an initial stream of liquid metal from a tundish 2 into a mold 3 with an initial flow rate FRini using a continuous casting nozzle 1 comprising at least:
  • the initial flow rate FRini is set from 0.3 T/min to 6 T/min
  • the gas flow rate GFR is regulated using a valve or a mass flowmeter - the gas flow rate GFR is set from 0.1 Nl/min to 5 Nl/min
  • the casting speed Vc is set from 0.4 m/min to 6 m/min
  • the ratio Q is set from 0.2 to 0.8
  • Fig 1 shows an embodiment of the installation used in the continuous casting process according to the invention.
  • the installation comprises a continuous casting nozzle 1 disposed between a tundish 2 and a mold 3.
  • the nozzle 1 is composed of an upper part 4 and a lower part 5.
  • a dome 6 is disposed at the inlet of the upper part 4 and closes a part of it.
  • the top of the dome 6 preferably has a slope of a certain angle, higher than 15° for example.
  • the dome 6 also has a lateral side, preferably forming a sharp edge with the slope.
  • the dome 6 is fixed to the upper part 4 by one or more support arms 7.
  • a means for injecting raw material 10 into at least one of the mixing chambers 9a, 9b and a means for injecting gas 1 1 are also comprised in the upper part 4, each one being partly located in one of the support arms 7 and passing through the dome 6.
  • the means for injecting raw material 10 is a powder injector.
  • the powder injector can be an endless screw, for example, linked to a powder tank.
  • the powder injector preferably has a diameter ranging from 10 to 30 mm.
  • the powder injector also preferably has an angle ranging from 30 to 90° with respect to the horizontal in a usage configuration. More preferably, the powder injector has an angle ranging from 30 to 50° with respect to the horizontal.
  • the lower part 5 of the nozzle 1 is composed of at least two channels 12a, 12b, 12c, extending from the chambers 9a, 9b of the upper part 4 after the reduction of their section, and opening into the mold 3, through at least one outlet 13 for each channel 12a, 12b, 12c.
  • three channels 12a, 12b, 12c, are present.
  • the channels 12a, 12b, 12c are of circular shape. In a preferred embodiment, the channels 12a, 12b, 12c have a round, an elliptic or an oblong section.
  • At least one of the channels 12a, 12b, 12c has a length different than the other channels 12a, 12b, 12c. As shown on Fig 1 , one channel 12a is longer than the other channels 12b, 12c, but other configurations can be considered with only two channels or two longer channels.
  • the channels 12a, 12b, 12c having different lengths are connected to separate chambers 9a, 9b, but more than one channel 12a, 12b, 12c can be connected to a single chamber 9a, 9b.
  • two chambers 9a, 9b and three channels 12a, 12b, 12c, are present.
  • the longer channel 12a is connected to one chamber 9a and the two other shorter channels 12b, 12c are connected to the other chamber 9b.
  • the longer channel 12a has two outlets 13 located on the side of the channel 12a, have an angle with respect to the horizontal and the bottom of the channel 12a has a dome shape.
  • the outlets 13 are located on the side of the channels 12a, 12b, 12c
  • the bottom of the channel 12a, 12b, 12c has a flat, a recess, a slope or a dome shape.
  • Fig 6 shows various shapes for the bottom of the channels
  • Fig 6a shows a flat shape for a channel 12a, 12b, 12c with only one outlet
  • Fig 6b shows a recess shape for a channel 12a, 12b, 12c with only one outlet
  • Fig 6c shows a slope shape for a channel 12a, 12b, 12c with only one outlet
  • Fig 6d shows a flat shape for a channel 12a, 12b, 12c with two outlets
  • Fig 6e shows a recess shape for a channel 12a, 12b, 12c with two outlets 13
  • Fig 6f shows a dome shape for a channel 12a, 12b, 12c with two outlets 13.
  • the shapes represented in Fig 6 are only given as examples and the bottom of the channels 12a, 12b, 12c can be of any shape.
  • the method of continuous casting of the invention consists in manufacturing a composite metallic product having a distinct shell 16 and bulk 17 which are of different composition, maximizing said difference of composition between the shell 16 and the bulk 17, while allowing the thickness of the shell 16 to remain equal to the target value in the final product.
  • the method comprises four steps.
  • the dome 6, being placed in the trajectory of the steel, forces the initial stream to collide on it.
  • the slope of the dome 6 makes the steel flow towards its edge.
  • the support arms 7 create different areas on the dome 6, splitting the initial stream of steel into a plurality of separate streams. The number of separate streams is determined by the design of the dome 6 and its support arms 7.
  • the separate streams flow then into the different mixing chambers 9a, 9b.
  • the design of the internal wall 8 separating the chambers 9a, 9b determines the repartition of the separate streams into each chamber 9a, 9b by determining their respective volume.
  • the steel accumulates then inside the chambers 9a, 9b due to the reduction of their section.
  • the steel is then distributed into the channels 12a, 12b, 12c and poured into the mold 3 through the outlets 13 of the channels 12a, 12b, 12c.
  • the flows of liquid steel 20 coming from the outlets 13 having the immersion depth D1 are the upper flows 20.
  • the total flow rate of the upper flows FRup is a fraction Q of the initial flow rate FRini injected at the top of the nozzle 1 .
  • the flows of liquid steel 21 coming from the outlets 13 having the immersion depth D2 are the lower flows 21 .
  • the total flow rate of the lower flows FRIow is the other fraction (1 -Q) of the initial flow rate FRini.
  • Fig 4 shows the repartition of the flows of liquid steel, according to the embodiment of Fig 1 , using the Q ratio.
  • FRup is partitioned between the two upper outlets 13, with each upper outlet 13 having a flow rate coming out of it of (Q/2)*FRini.
  • the flow rates are partitioned between the outlets 13 having the same immersion depth.
  • the flow rate FRup is partitioned between all the outlets 13 having an immersion depth D1 and the flow rate FRIow is partitioned between all the outlets 13 having an immersion depth D2.
  • the diameter of the outlets respectively to the diameter of the channels is defined to regulate the speed of the flows of liquid metal flowing out of the outlets.
  • the second step consists in injecting raw material into at least one of the chambers 9a, 9b to modify the composition of the steel flowing into said chamber 9a, 9b.
  • the design of the chambers 9a, 9b having a large section at the top allows the steel to flow down the dome 6 like a waterfall and allows the raw material to be injected into the flow without the steel coming into contact with the means for injecting raw material 10.
  • the design of the chambers 9a, 9b allows the steel to be slowed down and to accumulate in the chambers 9a, 9b.
  • the reduction of the section of the chambers allows the steel to be agitated inside the chamber. In consequence, the raw material injected can be mixed efficiently with the steel into said chamber 9a, 9b to modify its composition, and starts melting.
  • the raw material injected into the steel is in the form of powder. It can be of various composition, for example, it can be FeSi, Ni, FeAl, FeTi, FeCr, FeNb, FeB, FeCe, FeMo, etc...
  • Fig 5 shows a cross-sectional view of the dome 6 and the top of the mixing chambers 9a, 9b as well as an embodiment of the means for injecting raw material 10.
  • the ending part of the means for injecting raw material 10 is located inside the dome 6 and one of its support arms 7 and opens under the dome 6. It injects raw material into one of the mixing chambers 9a, 9b.
  • the injection of raw material is oriented towards the metal steel streams flowing down the dome 6. It allows a better mixing of the raw material into the mixing chambers 9a, 9b.
  • the means for injecting raw material 10 has an angle with respect to the horizontal which is preferably from 30° to 90°. More preferably, the angle is from from 30 to 50°.
  • the different chambers 9a, 9b contain two types of steel with different composition.
  • the two types of steel are poured at the two different heights into the mold 3.
  • the upper flows 20 and the lower flows 21 create two pools of steel, an upper pool 14 and a lower pool 15, different in composition and separated by an interface 19 at a depth Li.
  • the composition of the pools 14, 15 varies depending on the chamber 9a, 9b where the raw material is injected. If the raw material is injected into a chamber 9a, 9b connected to longer channels 12a, the composition of the upper pool 14 is the composition of the steel coming from the tundish 2 only and the composition of the lower pool 15 is the combination of the composition of the steel coming from the tundish 2 and the composition of the raw material injected.
  • the composition of the upper pool 14 is the combination of the composition of the steel coming from the tundish 2 and the composition of the raw material injected and the composition of the lower pool 15 is the composition of the steel coming from the tundish 2 only.
  • the raw material can thus be injected into any of the chambers
  • the third step consists in injecting gas below the dome 6 with a defined gas flowrate GFR.
  • This step facilitates the injection of raw material into the chambers 9a, 9b by creating a gas flow which maintains the steel flowing down the dome 6 towards the exterior of the upper part 4, thus creating a zone below the dome 6 without steel. This hollow zone prevents any contact between the steel and the raw material injection 10 thus avoiding potential clogging of the injection.
  • the gas is preferably non-oxidizing, Ar for example, to prevent any reaction with the steel during casting.
  • the gas flow is regulated using a valve or a mass flowmeter.
  • the gas flow rate GFR is set from 0.1 Nl/min to 5 Nl/min.
  • the fourth step consists in regulating the different parameters to define the depth Li of the interface 19 between the two pools 14, 15 in the mold 3 and to stabilize it, in order to maximize the difference of composition between the shell 16 and the bulk 17 of the composite metallic product as well as keeping constant the thickness of the shell 16 of said product.
  • the main parameters that can be regulated are the initial flow rate of steel FRini, the gas flow rate GFR, the outlets 13 immersion depths D1 and D2 and the casting speed Vc.
  • the thickness of the solidified part can be determined by a formula. With e being the solidified thickness: e: solidified thickness (mm)
  • Vc casting speed (m.min-1 ) k: constant depending on the cooling speed of the caster
  • the casting length L is a variable representing the distance from the meniscus of the liquid steel to a variable depth in the mold 3.
  • the steel of the upper pool 14 solidifies first, creating a solidified part with one composition.
  • the solidified thickness grows until it reaches the interface 19 between the two pools 14, 15 where the second composition in the lower pool 15 starts to solidify until total solidification of the product.
  • the first solidified composition coming from the upper pool 14 represents the shell 16 of the product and the second composition coming from the lower pool 15 represents the bulk 17 of the product.
  • the material obtained is a composite metallic product with a composition different in its shell 16 than in its bulk 17 as illustrated by Fig 2.
  • the thickness of the shell 16 of the composite metallic product can be calculated.
  • the thickness of the shell 16 is calculated using the distance Li between the meniscus of the liquid steel and the position of the interface 19 between the upper pool 14 and the lower pool 15.
  • Fig 3 represents an embodiment of the lower part 5 of the nozzle 1 used in the continuous casting process and the mold 3 where it is immersed.
  • the outlets 13 of the shorter channels 12b, 12c are immersed into the mold 3 at an immersion depth D1 and the outlets 13 of the longer channels 12a are immersed into the mold 3 at an immersion depth D2 > D1 .
  • the immersion depth D1 or D2 represents the distance from the meniscus of the liquid steel to the top of the outlet 13, like represented in Fig 3.
  • the distance D1 or D2 represents the distance from the meniscus of the liquid steel to the bottom of the channel 12a, 12b, 12c.
  • D1 and D2 are parameters that are defined by the casting conditions.
  • the gap A between the outlets 13 of the shorter channels 12b, 12c and the outlets 13 of the longer channels 12a, contrary to D1 and D2, is a fixed distance only determined by the design of the nozzle 1. Its value can be calculated using the following formula:
  • the steel for the upper pool 14 is poured into the mold 3 through the outlets 13 of the shorter channels 12b, 12c creating upper flows 20 at the depth D1
  • the steel for the lower pool 15 is poured into the mold 3 through the outlets 13 of the longer channels 12a creating lower flows 21 at the depth D2.
  • the interface 19 between the two pools is created where the upper flows 20 and the lower flows 21 meet.
  • Vc is set from 0.4 m/min to 6 m/min.
  • the products obtained by this method are preferably billets, blooms, or slabs.
  • the continuous casting process meets the expectations in terms of quality of the semi-finished product. It allows a stable casting of a composite metallic product having a distinct shell 16 and bulk 17, having a maximized difference in composition between said shell 16 and bulk 17 and the thickness of said shell 16 is constant in the final product.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Continuous Casting (AREA)

Abstract

L'invention concerne un procédé de coulée continue d'un produit métallique composite comportant une enveloppe et un volume distincts présentant des compositions différentes, ladite enveloppe présentant une épaisseur constante, ledit procédé comprenant les étapes consistant à : A. verser un flux initial de métal liquide depuis un panier de coulée dans un moule avec un débit initial FRini à l'aide d'une buse de coulée continue, B. injecter une matière première dans au moins l'une desdites chambres de mélange en vue de son mélange avec du métal liquide s'écoulant dans ladite chambre de mélange pour modifier sa composition, C. injecter un gaz sous ledit dôme avec un débit de gaz défini GFR, D. réguler le débit initial FRini, le débit de gaz GFR, les profondeurs d'immersion des orifices de sortie D1 et D2 et la vitesse de coulée Vc pour obtenir un produit métallique composite.
PCT/IB2023/060908 2023-10-30 2023-10-30 Procédé de coulée continue d'un produit métallique composite Pending WO2025093902A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/IB2023/060908 WO2025093902A1 (fr) 2023-10-30 2023-10-30 Procédé de coulée continue d'un produit métallique composite

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/IB2023/060908 WO2025093902A1 (fr) 2023-10-30 2023-10-30 Procédé de coulée continue d'un produit métallique composite

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WO2025093902A1 true WO2025093902A1 (fr) 2025-05-08

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11197807A (ja) 1998-01-08 1999-07-27 Kawasaki Steel Corp 複層鋳片鋳造用浸漬ノズルおよび複層鋳片の製造方法
EP2099576B1 (fr) * 2006-12-12 2010-05-19 Centre De Recherches Metallurgiques ASBL-centrum Busette a jet creux pour coulee continue d'acier
US9498822B2 (en) * 2012-03-28 2016-11-22 Arcelormittal Investigacion Y Desarrollo, S.L. Continuous casting equipment

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11197807A (ja) 1998-01-08 1999-07-27 Kawasaki Steel Corp 複層鋳片鋳造用浸漬ノズルおよび複層鋳片の製造方法
EP2099576B1 (fr) * 2006-12-12 2010-05-19 Centre De Recherches Metallurgiques ASBL-centrum Busette a jet creux pour coulee continue d'acier
US9498822B2 (en) * 2012-03-28 2016-11-22 Arcelormittal Investigacion Y Desarrollo, S.L. Continuous casting equipment

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