US20090255642A1 - Stirrer - Google Patents

Stirrer Download PDF

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Publication number
US20090255642A1
US20090255642A1 US12/298,537 US29853707A US2009255642A1 US 20090255642 A1 US20090255642 A1 US 20090255642A1 US 29853707 A US29853707 A US 29853707A US 2009255642 A1 US2009255642 A1 US 2009255642A1
Authority
US
United States
Prior art keywords
meniscus
iron core
mould
mold
casting
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.)
Abandoned
Application number
US12/298,537
Other languages
English (en)
Inventor
Sten Kollberg
Jan-Erik Eriksson
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.)
ABB AB
Original Assignee
ABB AB
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 ABB AB filed Critical ABB AB
Assigned to ABB AB reassignment ABB AB ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: KOLLBERG, STEN, ERIKSSON, JAN-ERIK
Publication of US20090255642A1 publication Critical patent/US20090255642A1/en
Priority to US13/402,144 priority Critical patent/US20120199308A1/en
Abandoned 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
    • B22D11/10—Supplying or treating molten metal
    • B22D11/11—Treating the molten metal
    • B22D11/114—Treating the molten metal by using agitating or vibrating means
    • B22D11/115—Treating the molten metal by using agitating or vibrating means by using magnetic fields
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D27/00—Treating the metal in the mould while it is molten or ductile ; Pressure or vacuum casting
    • B22D27/02—Use of electric or magnetic effects
    • 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
    • B22D41/08—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like for bottom pouring
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C9/00—Alloys based on copper

Definitions

  • the present invention relates to a device for continuous or semicontinuous casting of metals, comprising a stirrer according to the preamble to claim 1 .
  • a molten metal is supplied to a casting mould, hereinafter designated mould, in which it is cooled and formed into an elongated strand.
  • the strand is designated BILLET, BLOOM or SLAB.
  • a primary flow of hot, molten metal is supplied to the cooled mould, in which the metal is cooled and at least partially solidifies into an elongated strand.
  • the cooled and partially solidified strand then continuously leaves the mould. At the point where the strand leaves the mould, it has at least a mechanically self-supporting, solidified casing that surrounds a non-solidified centre.
  • the cooled mould is open at two opposite ends in the casting direction and preferably connected to means for supporting the mould and means for supplying coolant to the mould and supporting means.
  • the mould is preferably made of a copper-based alloy with good thermal conductivity.
  • the molten metal is supplied to the mould via a casting tube that extends down in to the mould.
  • the casting tube preferably extends so far down into the mould that it projects into the molten metal that exists therein.
  • the primary flow leads downwards in the casting direction
  • the secondary flow leads from the region of the walls of the mould upwards towards the surface of the metal bath located therein, designated the meniscus, and downwards.
  • the meniscus is covered by a layer consisting of casting powder intended to act as protection against the surrounding atmosphere and to minimize heat losses.
  • hot metal flow is allowed to enter into the mould in an uncontrolled manner, the flow will penetrate deep into the cast strand, which probably will have a negative influence on the quality and productivity.
  • An uncontrolled hot metal flow in the cast strand may result in encapsulation of non-metallic particles and/or gas occlusions in the solidified strand, or cause casting defects in the inner structure of the cast strand.
  • a deep penetration of hot metal flow may also cause a partial remelting of the solidified surface structure so that the melt penetrates the surface layer below the mould, which causes severe disturbances in production and a long downtime for repair.
  • Velocity variations caused by oscillating flow in the mould give rise to pressure variations at the meniscus, and, in addition, variations in height arise at the meniscus.
  • Velocity variations caused by oscillating flow in the mould give rise to pressure variations at the meniscus, and, in addition, variations in height arise at the meniscus.
  • the velocity of flow and hence the turbulence at the meniscus become too high, this leads to slag being drawn down from the casting powder and further down into the solidified strand, and results in an increased risk of cracking due to uneven shell growth.
  • the object of the present invention is to provide a device for continuous or semicontinuous casting of metals, especially intended for casting of slabs, which contributes to reduce or eliminate the disadvantages mentioned above.
  • a device is aimed at which creates an even flow at the meniscus for different speeds of the inflowing melt.
  • the metal flow at the meniscus is directed away from the narrow sides of the mould inwards towards the casting tube and uniformly across the whole width of the melt, and, in addition, a homogeneous flow configuration is obtained at the meniscus which provides the lowest turbulence when the flow is uniform across the whole mould width.
  • a stirrer placed as previously described a sufficiently large counter-directed meniscus flow is obtained uniformly over the whole width of the casting mould while at the same time the turbulence is restricted.
  • the location of the stirrer also contributes to obtain a good rotation of the melt around the casting tube and the installation of the stirrer is considerably simpler compared with prior art solutions.
  • the secondary flow is utilized in an optimum way while at the same time, with the help of the stirrer, it is modified so as to obtain a good symmetrical flow of the melt in the mould including a good horizontal flow of the melt around the casting tube, which promotes an even shell growth while at the same time the amount of inclusions in the finished strand is reduced.
  • an optimum flow is meant that the velocity of the melt at the meniscus (the secondary flow) is maintained at a constant level without varying in time while at the same time the velocity of the metal flow (the primary flow) directed downwards from the casting tube is to be kept at as low a level as possible to minimize the risk of inclusions accompanying the melt far down into the solidified strand.
  • the dimension of the iron cores of the stirrer in the vertical direction is usually 240-280 mm.
  • the iron core is arranged such that its upper part is positioned at a distance away from the meniscus that lies from 50 mm above the surface of the meniscus to 150 mm below said surface.
  • the iron core is arranged such that its upper part is positioned at a distance away from the meniscus that lies from 50 mm above the surface of the meniscus to 100 mm below said surface.
  • two stirrers are arranged symmetrically around the centre line of the broad sides of the mould and on both sides of said broad sides. Since the iron cores of the stirrers only need to cover part of the width of the cast strand, such a device provides a cost-effective solution since a good rotation of the melt around the casting tube as well as an even velocity profile over the thickness of the width of the cast strand are obtained.
  • stirrers are placed asymmetrically, on respective sides of the long sides of the mould.
  • This embodiment provides advantages such as lower weight, lower power consumption and reduced influence of magnetic fields on the surroundings.
  • the pole pitch is large, which results in a maximally effective stirrer.
  • FIG. 1 is an explanatory sketch of the device according to the invention.
  • FIG. 2 is a top view according to one embodiment of the device according to the invention.
  • FIG. 3 is an exploded view of a continuous casting device according to the invention.
  • FIG. 1 shows an explanatory sketch of the invention, comprising a mould 1 enclosing a melt 2 which is supplied to the mould 1 by means of a casting tube 3 lowered into the melt.
  • the melt 2 is cooled and a partially solidified strand is formed.
  • the strand is then moved continuously out of the mould 1 .
  • at least one stirrer 4 is arranged which has an iron core and a coil applied around it and, with the iron cores arranged so as not to cover the whole length of the broad sides of the mould but instead at least 50% of the broad sides of the mould and at most 80% of the broad sides of the mould, symmetrically about the centre line 5 of the mould 1 on both sides of the broad sides of the mould.
  • the iron cores are arranged such that their upper parts are positioned at a distance from the meniscus that lies from 50 mm above the surface 7 of the meniscus to 195 mm below said surface 7 , in order to create a rotating stirring of the melt below the meniscus 7 by means of a period low-frequency travelling field.
  • FIG. 2 shows an alternative embodiment of the invention, wherein the stirrers 8 are located asymmetrically on respective sides of the broad sides 10 of the mould 9 and arranged such that the upper parts of the iron cores are positioned at a distance from the meniscus that lies from 50 mm above the surface of the meniscus to 195 mm below said surface.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Continuous Casting (AREA)
US12/298,537 2006-04-25 2007-04-25 Stirrer Abandoned US20090255642A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US13/402,144 US20120199308A1 (en) 2006-04-25 2012-02-22 Stirrer

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
SE0600919 2006-04-25
SE0600919-5 2006-04-25
PCT/SE2007/050269 WO2007123485A1 (en) 2006-04-25 2007-04-25 A stirrer

Publications (1)

Publication Number Publication Date
US20090255642A1 true US20090255642A1 (en) 2009-10-15

Family

ID=38625289

Family Applications (2)

Application Number Title Priority Date Filing Date
US12/298,537 Abandoned US20090255642A1 (en) 2006-04-25 2007-04-25 Stirrer
US13/402,144 Abandoned US20120199308A1 (en) 2006-04-25 2012-02-22 Stirrer

Family Applications After (1)

Application Number Title Priority Date Filing Date
US13/402,144 Abandoned US20120199308A1 (en) 2006-04-25 2012-02-22 Stirrer

Country Status (7)

Country Link
US (2) US20090255642A1 (de)
EP (1) EP2010346A4 (de)
JP (1) JP2009535216A (de)
KR (1) KR20090016445A (de)
CN (1) CN101410204B (de)
RU (1) RU2419508C2 (de)
WO (1) WO2007123485A1 (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20180304349A1 (en) * 2015-10-30 2018-10-25 Nippon Steel & Sumitomo Metal Corporation Continuous casting apparatus and continuous casting method for multilayered slab

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4565238A (en) * 1981-12-11 1986-01-21 Kawasaki Steel Corporation Method of stirring molten steel in a continuously casting mold and an apparatus therefor

Family Cites Families (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5717355A (en) * 1980-07-02 1982-01-29 Nippon Kokan Kk <Nkk> Method for electromagnetic stirring of molten sheet within mold in slab continuous casting
JPS5775268A (en) * 1980-10-30 1982-05-11 Nippon Kokan Kk <Nkk> Electromagnetic stirring method for molten steel in mold in continuous casting plant
JPS6114052A (ja) * 1984-06-28 1986-01-22 Toshiba Corp 電磁撹拌方法
US4746268A (en) * 1987-07-29 1988-05-24 Hitachi, Ltd. End face mechanical shaft seal for use in hydraulic machines and seal ring assembly for use in the shaft seal
US5085265A (en) * 1990-03-23 1992-02-04 Nkk Corporation Method for continuous casting of molten steel and apparatus therefor
JPH07314104A (ja) * 1994-05-24 1995-12-05 Nippon Steel Corp 連続鋳造における鋳型内溶鋼流動制御法
IT1288900B1 (it) * 1996-05-13 1998-09-25 Danieli Off Mecc Procedimento di colata continua con campo magnetico pulsante e relativo dispositivo
JP3267545B2 (ja) * 1997-12-25 2002-03-18 川崎製鉄株式会社 連続鋳造方法
BR9912315A (pt) * 1998-07-24 2001-10-16 Gibbs Die Casting Aluminum Aparelho e método de fundição semi-sólida
JP2000061599A (ja) * 1998-08-26 2000-02-29 Sumitomo Metal Ind Ltd 連続鋳造方法
FR2801523B1 (fr) * 1999-11-25 2001-12-28 Usinor Procede de coulee continue des metaux du type utilisant des champs electromagnetiques, et lingotiere et installation de coulee pour sa mise en oeuvre
SE516850C2 (sv) * 2000-07-05 2002-03-12 Abb Ab Förfarande och anordning för styrning av omröring i en gjutsträng
JP3417906B2 (ja) * 2000-07-07 2003-06-16 株式会社神戸製鋼所 連続鋳造鋳型内の電磁攪拌方法
JP3651441B2 (ja) * 2002-01-31 2005-05-25 Ｊｆｅスチール株式会社 鋼の連続鋳造方法
WO2004050277A1 (en) * 2002-11-29 2004-06-17 Abb Ab Control system, computer program product, device and method
JP4256723B2 (ja) * 2003-06-05 2009-04-22 新日本製鐵株式会社 溶鋼の連続鋳造方法
JP2005238276A (ja) * 2004-02-26 2005-09-08 Nippon Steel Corp 電磁攪拌鋳造装置
JP4553639B2 (ja) * 2004-06-17 2010-09-29 株式会社神戸製鋼所 連続鋳造方法
JP4441384B2 (ja) * 2004-07-07 2010-03-31 新日本製鐵株式会社 連続鋳造方法ならびにストランドプール内流動制御装置

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4565238A (en) * 1981-12-11 1986-01-21 Kawasaki Steel Corporation Method of stirring molten steel in a continuously casting mold and an apparatus therefor

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20180304349A1 (en) * 2015-10-30 2018-10-25 Nippon Steel & Sumitomo Metal Corporation Continuous casting apparatus and continuous casting method for multilayered slab
US10987730B2 (en) * 2015-10-30 2021-04-27 Nippon Steel Corporation Continuous casting apparatus and continuous casting method for multilayered slab

Also Published As

Publication number Publication date
US20120199308A1 (en) 2012-08-09
WO2007123485A1 (en) 2007-11-01
EP2010346A4 (de) 2013-02-20
RU2419508C2 (ru) 2011-05-27
KR20090016445A (ko) 2009-02-13
EP2010346A1 (de) 2009-01-07
CN101410204B (zh) 2011-03-02
CN101410204A (zh) 2009-04-15
RU2008141879A (ru) 2010-05-27
JP2009535216A (ja) 2009-10-01

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AS Assignment

Owner name: ABB AB, SWEDEN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:KOLLBERG, STEN;ERIKSSON, JAN-ERIK;REEL/FRAME:021755/0937;SIGNING DATES FROM 20060826 TO 20080826

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION