US3584677A - Formation of continuous casting starter plugs - Google Patents

Formation of continuous casting starter plugs Download PDF

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Publication number
US3584677A
US3584677A US760586A US3584677DA US3584677A US 3584677 A US3584677 A US 3584677A US 760586 A US760586 A US 760586A US 3584677D A US3584677D A US 3584677DA US 3584677 A US3584677 A US 3584677A
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United States
Prior art keywords
refractory
shape
molten metal
mould
process according
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
US760586A
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English (en)
Inventor
Roderic Hugh Hammerton
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.)
Foseco International Ltd
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Foseco International Ltd
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 Foseco International Ltd filed Critical Foseco International Ltd
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    • 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
    • B22D11/08—Accessories for starting the casting procedure
    • B22D11/086—Means for connecting cast ingots of different sizes or compositions

Definitions

  • the present invention relates to the continuous casting of molten metal.
  • molten metal is poured from a ladle via a tundish into the top ofa mould having walls, usually ofcopper, through which cooling liquid, usually water, is circulated.
  • the solidified metal is withdrawn by a series of withdrawal rollers which grip the solidified metal issuing from the base of this mould as a continuous strand, which passes through a secondary cooling station where water is sprayed directly onto it.
  • the strand is subsequently cut into slabs of desired lengths for further processing.
  • a plug is inserted into th base of the mould, and molten metal then teemed into the mould.
  • the plug is withdrawn and continuous pulling of the cast strand commences.
  • the plug must be of such configuration on its upper surface that the just solidified strand holds firmly to the plug and therefore is pulled from the mould as the plug is withdrawn.
  • Such a configuration is herein called, for brevity, a key configuration.
  • the pltig usually used is a metal casting which is removably attached to a flexible bar known as a dummy bar. Before casting commences, the dummy bar must be raised through the withdrawal rollers and attached to the plug to ensure guidance of the cast strand through the rollers.
  • the plug castings are expensive, especially whenmoulds of large crosssectional area are used, and it is common practice to attempt to recover the casting from the piece of the solidified strand first cropped. Such recovery is itself an expensive process, the most practiced method being to try to cut away the strand from the casting with a flame cutter. This operation is a relatively simple one providing that the strand has not welded onto the casting.
  • a further necessary feature of such a casting is that it should fit exactly into the casting mould and it may not do so if damaged by the flame-cutting operation.
  • a process for the production of a continuous casting starter plug which comprises, at the close of a continuous casting operation, inserting into the molten metal at the top of a continuous casting mould a refractory shape, allowing the molten metal to solidify at the metal/refractory interface of said shape so that it acquires a key configuration as hereinbefore defined, removing said shape, withdrawing the solidified strand from the mould and cutting the last section of the strand from the solidified strand, said last section thereby constituting a starter plug or, more advantageously, a unitary starter plug/dummy bar.
  • a starter plug may be formed at the end of each continuous casting operation, for use in the next casting operation.
  • the method has several other advantages: the starter plug is automatically of the correct mould size and configuration; use is made of metal otherwise due to be cropped and discarded as scrap; the method is extremely simple to effeet, the majority of the steps being already necessary at the terminating ofcontinuous casting.
  • the above proposal could not be adopted, mainly because of the difficulties involved in removing the refractory from the cast key configuration; the use of tools to chip away the refractory shape from the solidified key configuration within the casting mould could not be practiced because of the danger of damaging the mould; removal at a position immediately adjacent to the mould, after withdrawal through the mould base, involves the risk of spillage of the refractory materialon to the lower portions of the continuous casting plant and resultant abrasive damage thereto; complete withdrawal of the cast strand and refractory shape through the withdrawal rollers etc. for clean ing would partly defeat the object of the method since the section cropped as dummy bar and key configuration would then have to be treated in the conventional manner, i.e. it would need to be raised through the rollers to be repositioned in the mould.
  • Foaming agent Liquid urea-formaldehyde resin. Water.... Refractory (silica sand-60 mesh BSS) Mixture ll:
  • Foaming agent Teepolzaqueous solution
  • Organic fibre wood pulp
  • Water Catalyst phosphoric acid
  • u 3 rc NP b l -uaag cataract
  • the bench life of each mixture extends over days and may be regarded as indefinite.
  • the two mixtures are mixed together by any convenient means, and the resulting composition moulded to the required shape.
  • the formed slab sets to a rubbery state in a predetermined time depending on the proportion of catalyst used.
  • the metalcontacting surface of the slab is rendered nonporous by pressing against the slab a oO-mesh perforated metal sheet.
  • Final hardening may either be effected by leaving at room temperature, e.g. for 6 to 10 minutes when a high concentration of catalyst is used, or by heating by any suitable means, e.g. ovens or dielectric heating, for a similar period of time when a low concentration of catalyst is used.
  • the type of refractory used in the manufacture of the bonded shape is unimportant, and it may be chosen from a wide variety of available materials such as sand, chamotte, grog, zircon flour, chromite flour, alumina or magnesia.
  • the bonded refractory shape may include organic fibrous material which increases mechanical strength of the shape prior to use, but in use burns out and aids the slab in disintegration.
  • compositions are very effective insulating materials and they tend to maintain the cast metal in a molten condition for a prolonged period.
  • molten metal In view of this, and their tendency to disintegrate when contacted by molten metal, there is a danger that premature disintegration, while the metal is maintained in a molten state, will lead to loss of the desired key configuration. Therefore it is desirable to provide the refractory shape with a means of chilling the metal with which it comes into contact so that the metal solidifies before the refractory shape disintegrates.
  • the chilling effect may be induced in a number of ways; for example, ingredients having a high heat capacity may be incorporated in the insulating composition, powdered iron being one such suitable material; al-
  • the surface of the refractory to be contacted by molten metal may be provided with a bonded coating of powdered metal, such as powdered ferrosilicon or powdered iron applied with a suitable adhesive or binding agent (e.g. sodium silicate); more preferably however the metal-contacting portion of the refractory shape is covered with thin steel sheet. For this purpose a thickness of one-eighth inch steel sheet has been found to be satisfactory.
  • powdered metal such as powdered ferrosilicon or powdered iron applied with a suitable adhesive or binding agent (e.g. sodium silicate); more preferably however the metal-contacting portion of the refractory shape is covered with thin steel sheet.
  • a thickness of one-eighth inch steel sheet has been found to be satisfactory.
  • a preferred refractory shape is a ring of shape similar to the cross section of the mould, and of cross section parallel to the plane of the ring greater toward one side of the ring than the other; in use the side of larger cross section is placed downward.
  • a firm dovetail" formation may be formed in the end of one strand.
  • the ring should preferably extend to the sides of the mould, in order to avoid the formation of fins between the refractory ring and the mould wall, which may tend to become turned outward and thus damage the mould on insertion of the starting plug.
  • the outside of the ring may be coated with a lubricating coating such as a graphite-containing coating.
  • the refractory shape is placed in the top of the continuous casting mould at the termination of the normal teeming. Backfilling is then practiced to take up the pipe formed due to shrinkage of metal while it cools and in order to ensure formation of a satisfactory casting around the refractory shape.
  • the withdrawal of the cast strand is usually interrupted for a few minutes during this process and this further necessitates a temporary closing down or reduction of activity of the secondary cooling plant.
  • the disintegrated refractory material is preferably removed from the solidified metal in the mould using vacuum suction in order to minimize the risk of spillage of refractory material onto the lower portions of the continuous casting plant.
  • the strand may then be withdrawn from the mould and the starter plug cut away as part of the normal cropping operation.
  • the plug it is preferable to allow the plug to remain within the mould for commencement of the following casting operation.
  • the strand is cropped below the withdrawal and guide rollers, leaving a unitary starter plug/dummy bar in the correct position for the following cast, which may then proceed after a much shorter time interval, providing molten metal for casting is available, thereby leading to a greatly increased output from the casting machine.
  • a secondary advantage is that this technique eliminates the problems caused by an unreliable connection between a conventional dummy bar and starter plug and the attendant damage to such items during use.
  • FIG. 1 shows a cross section through a continuous casting mould just after the insertion of the refractory shape in the process of the present invention
  • FIG. 2 is a perspective view of a refractory ring.
  • FIG. 1 there is shown a continuous casting mould l in which is cast a strand of metal 2.
  • a refractory ring 3 which is coated at 4 with a graphite-containing lubricating composition and which fits the mould exactly.
  • the ring is lined with one-eighth inch steel plate 5. Backfilling hasjust been terminated, filling up the pipe formed at 6, and giving a sound upper end to the cast strand. The ring is subsequently removed and the strand withdrawn,
  • This last portion may then be fed back into the base of the mould and used as a starter plug as described above.
  • FIG. 2 shows the refractory ring used. The parts noted above are numbered as noted therein.
  • refractory shape used is a ring of shape similar to the cross section of the mould, and of cross section parallel to the plane of the ring greater toward one side of the ring than the other.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Furnace Housings, Linings, Walls, And Ceilings (AREA)
  • Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
  • Mold Materials And Core Materials (AREA)
US760586A 1967-09-26 1968-09-18 Formation of continuous casting starter plugs Expired - Lifetime US3584677A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB43800/67A GB1192438A (en) 1967-09-26 1967-09-26 Continuous Casting of Molten Metal

Publications (1)

Publication Number Publication Date
US3584677A true US3584677A (en) 1971-06-15

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Application Number Title Priority Date Filing Date
US760586A Expired - Lifetime US3584677A (en) 1967-09-26 1968-09-18 Formation of continuous casting starter plugs

Country Status (4)

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US (1) US3584677A (de)
AT (1) AT287945B (de)
DE (1) DE1783049A1 (de)
GB (1) GB1192438A (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140290899A1 (en) * 2011-12-05 2014-10-02 Siemens Vai Metals Technologies Gmbh Process engineering measures in a continuous casting machine at the start of casting, at the end of casting and when producing a transitional piece
WO2020175998A1 (en) 2019-02-26 2020-09-03 Ttap Drive As Drive system configured to provide frictional fit engagement

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111438343B (zh) * 2019-01-16 2021-08-13 宝山钢铁股份有限公司 一种用于防止连铸终浇冒涨事故的工装及其防止方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE674136C (de) * 1935-10-24 1939-04-05 Duerener Metallwerke A G Kokille zum ununterbrochenen Giessen dichter Bloecke
US2176990A (en) * 1937-08-18 1939-10-24 Chase Brass & Copper Co Apparatus for continuously casting metals
US2856658A (en) * 1956-08-13 1958-10-21 Koppers Co Inc Method of continuous casting
GB840676A (en) * 1957-04-10 1960-07-06 John Holroyd & Company Ltd Improvements in or relating to the casting of rods, tubes and the like

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE674136C (de) * 1935-10-24 1939-04-05 Duerener Metallwerke A G Kokille zum ununterbrochenen Giessen dichter Bloecke
US2176990A (en) * 1937-08-18 1939-10-24 Chase Brass & Copper Co Apparatus for continuously casting metals
US2856658A (en) * 1956-08-13 1958-10-21 Koppers Co Inc Method of continuous casting
GB840676A (en) * 1957-04-10 1960-07-06 John Holroyd & Company Ltd Improvements in or relating to the casting of rods, tubes and the like

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140290899A1 (en) * 2011-12-05 2014-10-02 Siemens Vai Metals Technologies Gmbh Process engineering measures in a continuous casting machine at the start of casting, at the end of casting and when producing a transitional piece
US9254520B2 (en) * 2011-12-05 2016-02-09 Siemens Vai Metals Technologies Gmbh Process engineering measures in a continuous casting machine at the start of casting, at the end of casting and when producing a transitional piece
WO2020175998A1 (en) 2019-02-26 2020-09-03 Ttap Drive As Drive system configured to provide frictional fit engagement
US11926021B2 (en) 2019-02-26 2024-03-12 Ttapdrive As Drive system configured to provide frictional fit engagement

Also Published As

Publication number Publication date
GB1192438A (en) 1970-05-20
AT287945B (de) 1971-02-10
DE1783049A1 (de) 1972-02-24

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