EP0268632B1 - Ameliorations dans la production de l'acier - Google Patents

Ameliorations dans la production de l'acier Download PDF

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Publication number
EP0268632B1
EP0268632B1 EP87903375A EP87903375A EP0268632B1 EP 0268632 B1 EP0268632 B1 EP 0268632B1 EP 87903375 A EP87903375 A EP 87903375A EP 87903375 A EP87903375 A EP 87903375A EP 0268632 B1 EP0268632 B1 EP 0268632B1
Authority
EP
European Patent Office
Prior art keywords
modifying agent
vessel
orifice
iron
wall
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.)
Expired - Lifetime
Application number
EP87903375A
Other languages
German (de)
English (en)
Other versions
EP0268632A1 (fr
Inventor
David William Stamp
James Kennedy
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.)
British Steel PLC
Original Assignee
British Steel PLC
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 British Steel PLC filed Critical British Steel PLC
Publication of EP0268632A1 publication Critical patent/EP0268632A1/fr
Application granted granted Critical
Publication of EP0268632B1 publication Critical patent/EP0268632B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime 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
    • B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
    • B22D41/14—Closures
    • B22D41/22—Closures sliding-gate type, i.e. having a fixed plate and a movable plate in sliding contact with each other for selective registry of their openings
    • B22D41/42—Features relating to gas injection
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D1/00—Treatment of fused masses in the ladle or the supply runners before casting
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C1/00—Refining of pig-iron; Cast iron
    • C21C1/10—Making spheroidal graphite cast-iron

Definitions

  • This invention relates to the production of iron, for casting and more particularly, the production of quasi-flake and spheroidal graphite iron.
  • quasi-flake and spheroidal graphite irons are hereinafter referred to as "modified iron”.
  • modified iron It is known to form modified iron by introducing into liquid iron, graphite modifying elements, alloys or mixtures, containing singly or in combination, the elements magnesium, cerium, calcium, sodium, yttrium and lithium. Any such additive is hereinafter referred to as a "modifying agent”.
  • a modifying agent Any such additive is hereinafter referred to as a "modifying agent”.
  • an inoculating element usually silicon, may be contained in the modifying agent or added separately, in which case it is hereinafter referred to as an "inoculating agent". In the case of quasi-flake, this is usually preceded by the addition to the molten iron of a material such as a ferrotitanium alloy.
  • proposals to add magnesium in the form of a briquette from above to the molten iron in a containing vessel usually involves a most violent reaction adjacent the surface in which a very high percentage (frequently more than 50%) of the magnesium does not, in fact, become absorbed in the iron but is lost by the severity of the reaction through the surface of the melt to the atmosphere.
  • a process for the production of modified iron for casting with quasi-flake or spheroidal graphite comprising the steps of containing the iron in molten form, in a prepared state for modifying, in a containing vessel having a sliding gate valve mounted in the wall thereof at or adjacent the base thereof, the sliding gate valve having at least two openings passing therethrough, a first opening being connected to a source of modifying agent containing material and being selectively moveable into and out of alignment with an orifice through the wall of the vessel, and the second opening being selectively moveable into and out of separate alignment with an orifice through the wall of the vessel to enable the discharge of metal from the vessel therethrough; characterised by the steps of moving the gate of the valve to align said one opening with an orifice and injecting modifying agent containing material entrained in inert gas through said first opening therein and an orifice in the wall of the vessel for the formation of modified iron therein, and subsequently moving the sliding gate to align the second opening with an or
  • the process of the present invention may include, as an initial step, the provision of a mass of powdered or granular refractory material in the well in the wall of the vessel above the orifice and the valve prior to the filling of the vessel with the molten iron, and blowing gas into the well prior to the injection of the modifying agent containing material such as to displace the refractory filler therefrom.
  • the filler material may be blown from the well in the wall of the vessel by means of a gas through a melt discharge opening of the sliding gate valve or through the inlet opening for the modifying agent containing material.
  • injection of the gas to clear the filler material may be by means of a tuyere extending within the thickness of a fixed plate of the sliding gate valve into the relevant well space.
  • a gas channel can be provided through a refractory brick of the wall of the metal vessel into the opening.
  • gas bubbling through the bottom orifice of a kind often used for stirring and other purposes in molten metal processes is, with the operation of the invention, to be avoided or at least reduced to a minimum during at least the majority of the operation, since such bubbling will tend to take the entrained modifying agent containing material to the surface of the melt where it can be lost to the atmosphere. Nevertheless it has been found advantageous to gas bubble for an optimum period of one half to two minutes at up to 50 Nl/min to effect separation of desulphurisation-deoxidation products, if temperature permits.
  • the modifying agent can be pneumatically conveyed into the liquid iron with low gas flow rates because of the attainment of high gas velocities and, hence, powder velocities which prevent metal ingress into the tuyere during the injection.
  • Typical gas flow rates used in this case would be 300 to 450 Nl/min, depending on the required powder flow rate.
  • the efficiency of the operation of the invention is ensured by maintaining a slow injection of the modifying agent containing material whereby the potentially violent reaction of the modifying agent with the iron can be contained without creating unduly disturbed conditions within the melt and therefore loss through the surface of the modifying agent.
  • magnesium injection rates in the range 3-6mg/minute can be satisfactory. Such rates compare with injections into steel for desulphurisation, for example, through a lance injection system of 50kg/minute. It is to be noted that the gas/solid ratio can be directly comparable to injection for desulphurisation, which is known in the art.
  • the iron melt may be held in its containing vessel at a relatively low temperature thereby reducing the violence of the reaction.
  • a typical injection commencement temperature for large section castings would be in the range 1290°C to 1340°C, an injection termination temperature range of 1270°C to 1280°C, and then a teeming temperature of 1270°C to 1280°C.
  • injection temperatures may need to be greater than 1450°C.
  • the magnesium containing material may be of any convenient nature such as a magnesium-lime granular mixture or magnesium-alumina-aluminium mix, or an alloy in granular form typical of those presently used for SG iron production, e.g. an Fe-Si-Mg alloy.
  • the modifying agent whether based on magnesium, calcium, sodium, yttrium or lithium is preferably in finely divided form, e.g. with a tuyere having an internal diameter of the order of 6mm, a powder grain size of no greater than 1.4mm has been shown to be desirable.
  • the invention utilising sliding gate valves in or adjacent the base of a vessel has considerable advantage over earlier arrangement for injecting modifying agent containing materials into iron for its modification.
  • the level of injection is the maximum possible below the surface of the melt, thereby ensuring maximum efficiency capability and minimum loss of the reactive or low boiling point modifying agent.
  • the ladle depth is typically 2.0 metres and therefore the lance injection depth will be 1.6 - 1.9 metres, depending on the type of lance used.
  • the point of entry of the modifying agent will be typically 2.4 metres below metal level; the additional 0.5m corresponding to the length of the channel formed by the well block and inner nozzle above the injection point in the sliding gate plate and the injection lance outlet to ladle floor distance.
  • the powder flow is usually started before immersion and is maintained until after the lance is withdrawn from the vessel.
  • the powder is injected and terminated under an already established metal head thereby conserving high value injection materials.
  • the material resulting in quasi-flake iron had a ferro titanium alloy added to the vessel before injection of the magensium. In all cases, it is to be noted that the absorption efficiency of the injected magnesium is around 70% or above.
  • the Table also illustrates a further advantage of the process in the ability to produce irons with trace sulphur levels (0.002% S) from a high initial sulphur content which is significantly lower than those resulting from many present iron magnesium modification techniques.
  • the base wall 22 and lining 28 of an iron containing ladles are provided with a refractory upper nozzle insert 23 carrying a tuyere block 24 through which passes an inner tuyere 25.
  • a lower nozzle block 26 is located in the wall 22 and engages with the static plate 27 of the sliding gate valve assembly 12.
  • a sliding plate 29 carries an injection tuyere 30 connecting with a source of injecting modifying agent material incorporating magnesium (not shown).
  • a well 31 formed in the lining 28 and the upper nozzle 23 above the inner tuyere 25 are filled with filler material 32 which also fills the tuyere 25.
  • the inner tuyere 25 and well 31 is filled to overflow with filler material with the gate 12 in the closed position.
  • the ladle is then filled with molten iron.
  • gas is supplied to the tuyere 30 and then this is indexed in the direction of arrow 13 of Figure 1 so that it aligns with the inner tuyere 25 as shown in Figure 2 and blows out the filler material 32.
  • injection of modifying agent containing material can commence. At the end of such injection, the gate 12 is indexed in the direction of arrow 14 of Figure 2 and thereby closed.
  • Figure 3 which illustrates fully apparatus for carrying out the process of the invention as specified in the claims
  • the valve 1 combines injection with melt discharge by means of a discharge inner nozzle in the vessel base.
  • the plate 4 is indexed so as to close the orifice for a brief period whilst the iron/modifying agent reaction is completed or alternatively to gas bubble at a very low flow rate (up 50 Nl/min) to effect separation of desulphurisation deoxidation products.
  • the plate is then indexed to align the inner nozzle 6 with the pouring nozzle 5 so that the iron, either in the form of quasi-flake or spheroidal graphite is poured from the vessel through the nozzle 5.
  • a second injection tuyere 40 is provided, so that if blockage or wear of tuyere 11 occurs, the tuyere 40 can be used in its stead.
  • the sliding gate assembly needs to be a four position gate.
  • any convenient tuyere configuration can be used, e.g. multi-hole, multiple or concentric.
  • the ladles may incorporate a lid with facilities for fume extraction or, alternatively, the lid may provide a pressure tight seal to allow modifying agent vapour to increase pressure above the melt thereby increasing modifying agent recovery or efficiency as is well known in the art.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
  • Compounds Of Iron (AREA)

Claims (6)

  1. Procédé pour la production de fer modifié pour fonderie avec du graphite sphéroïdal ou quasi en forme de flocons, comprenant les étapes consistant à placer le fer en fusion à l'état préparé pour la modification dans un récipient de confinement possédant une soupape à obturateur coulissant montée dans la paroi de ce dernier à sa base ou en position adjacente à cette dernière, la soupape à obturateur coulissant possédant au moins deux ouvertures qui la traversent, une première ouverture étant reliée à une source d'une matière contenant l'agent de modification et étant mobile de manière sélective pour venir se mettre dans une position d'alignement et de non-alignement avec un orifice pratiqué dans la paroi du récipient, et la seconde ouverture étant mobile de manière sélective pour venir se mettre en alignement et en non-alignement séparés avec un orifice pratiqué dans la paroi du récipient pour permettre la décharge du métal hors du récipient à travers l'ouverture; caractérisé par les étapes consistant à déplacer l'obturateur de la soupape pour mettre ladite première ouverture en alignement avec un orifice et à injecter la matière contenant l'agent de modification entraínée dans un gaz inerte à travers ladite première ouverture pratiquée dans la soupape et à travers un orifice pratiqué dans la paroi du récipient pour y former du fer modifié, et à déplacer par la suite l'obturateur coulissant pour mettre la seconde ouverture en alignement avec un orifice pratiqué dans la paroi du récipient pour ainsi couler en lingotière du fer modifié à partir du récipient.
  2. Procédé selon la revendication 1 pour la production de fer modifié pour fonderie, dans lequel on injecte l'agent de modification via une tuyère possédant un diamètre interne de l'ordre de 6 mm.
  3. Procédé selon la revendication 1 ou 2 pour la production de fer modifié pour fonderie, dans lequel l'agent de modification est du magnésium ou est à base de magnésium, caractérisé par le fait que l'on obtient une efficacité d'agent de modification d'environ 70% ou plus en utilisant un débit d'injection de l'agent de modification dans le domaine de 3 à 6 kg par minute.
  4. Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce que la matière contenant l'agent de modification est un mélange de magnésium-chaux ou un mélange de magnésium-alumine-aluminium.
  5. Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce que l'agent de modification contenant du magnésium est un alliage sous forme granulaire à base de magnésium.
  6. Procédé selon l'une quelconque des revendications précédentes, caractérisé par l'étape, faisant suite à l'étape d'injection de l'agent de modification, consistant à introduire du gaz bulle à bulle à travers l'orifice pratiqué dans la paroi du récipient pour ainsi réaliser la séparation des produits de désulfuration et de désoxydation de la masse fondue.
EP87903375A 1986-05-29 1987-05-27 Ameliorations dans la production de l'acier Expired - Lifetime EP0268632B1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
GB8613106 1986-05-29
GB868613106A GB8613106D0 (en) 1986-05-29 1986-05-29 Production of iron
PCT/GB1987/000362 WO1987007306A1 (fr) 1986-05-29 1987-05-27 Ameliorations dans la production de l'acier

Publications (2)

Publication Number Publication Date
EP0268632A1 EP0268632A1 (fr) 1988-06-01
EP0268632B1 true EP0268632B1 (fr) 1998-08-12

Family

ID=10598646

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87903375A Expired - Lifetime EP0268632B1 (fr) 1986-05-29 1987-05-27 Ameliorations dans la production de l'acier

Country Status (5)

Country Link
EP (1) EP0268632B1 (fr)
AT (1) ATE169687T1 (fr)
DE (1) DE3752209D1 (fr)
GB (1) GB8613106D0 (fr)
WO (1) WO1987007306A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103495710A (zh) * 2013-10-09 2014-01-08 河南省金太阳铸造有限公司 一种浇铸用的孕育剂料斗

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH679987A5 (fr) * 1989-11-28 1992-05-29 Fischer Ag Georg
SE469969B (sv) * 1992-03-11 1993-10-18 Inst Foer Produktions Och Arbe Förfarande och anordning för att säkerställa öppning av en ventil till en skänk för smält metall

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2822791C2 (de) * 1977-05-26 1983-12-08 Gruzinskij politechničeskij institut imeni V.I. Lenina, Tbilisi Vorrichtung zum Einführen pulverförmiger Reagenzien mittels eines Trägergasstromes in eine Metallschmelze
DE2800684A1 (de) * 1978-01-09 1979-07-12 British Steel Corp Verfahren zur behandlung geschmolzenen metalls in einem behaelter
AT359100B (de) * 1978-04-25 1980-10-27 Inteco Int Techn Beratung Anordnung zur behandlung von stahlschmelzen in der pfanne durch bodenblasen
DE3115108A1 (de) * 1981-04-14 1982-10-28 Purmetall Gesellschaft für Stahlveredelung GmbH u. Co Betriebskommanditgesellschaft, 4200 Oberhausen Gefaess fuer metallurgische schmelzen

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103495710A (zh) * 2013-10-09 2014-01-08 河南省金太阳铸造有限公司 一种浇铸用的孕育剂料斗

Also Published As

Publication number Publication date
WO1987007306A1 (fr) 1987-12-03
GB8613106D0 (en) 1986-07-02
ATE169687T1 (de) 1998-08-15
DE3752209D1 (de) 1998-09-17
EP0268632A1 (fr) 1988-06-01

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