US20050200057A1 - Nozzle for continuous casting of aluminum killed steel and continuous casting method - Google Patents

Nozzle for continuous casting of aluminum killed steel and continuous casting method Download PDF

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Publication number
US20050200057A1
US20050200057A1 US10/513,186 US51318605A US2005200057A1 US 20050200057 A1 US20050200057 A1 US 20050200057A1 US 51318605 A US51318605 A US 51318605A US 2005200057 A1 US2005200057 A1 US 2005200057A1
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US
United States
Prior art keywords
cao
inner hole
nozzle unit
refractories
surface area
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
US10/513,186
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English (en)
Inventor
Koji Ogata
Koichi Shimizu
Keisuke Asano
Toshiyuki Hokii
Joki Yoshitomi
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.)
LWB REGRACTORIES Co
Krosaki Harima Corp
LWB Refractories Co
Original Assignee
Individual
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
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Assigned to KROSAKIHARIMA CORPORATION, LWB REGRACTORIES COMPANY reassignment KROSAKIHARIMA CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: SHIMIZU, KOICHI, ASANO, KEISUKE, HOKII, TOSHIYUKI, OGATA, KOJI, YOSHITOMI, JOKI
Assigned to KROSAKIHARIMA CORPORATION, LWB REFRACTORIES COMPANY reassignment KROSAKIHARIMA CORPORATION CORRECTED COVER SHEET TO CORRECT ASSIGNEE NAME, PREVIOUSLY RECORDED AT REEL/FRAME 016130/0529-0533 (ASSIGNMENT OF ASSIGNOR'S INTEREST) Assignors: SHIMIZU, KOICHI, ASANO, KEISUKE, HOKII, TOSHIYUKI, OGATA, KOJI, YOSHITOMI, JOKI
Publication of US20050200057A1 publication Critical patent/US20050200057A1/en
Abandoned legal-status Critical Current

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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
    • B22D11/10—Supplying or treating molten metal
    • 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
    • B22D41/52—Manufacturing or repairing thereof
    • B22D41/54—Manufacturing or repairing thereof characterised by the materials used therefor
    • 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

Definitions

  • the present invention relates to a nozzle unit for continuous casting of aluminum-killed steel, and the use of the nozzle unit.
  • alumina inclusions are attached to the surface of an inner hole of a nozzle unit for use in casting (hereinafter referred to as “nozzle unit” for brevity), and agglomerated to form a large-size alumina particles.
  • the agglomerated alumina particles are mixed in the molten steel flow, and incorporated into slabs as large-size inclusions to cause defect or deteriorated quality in the slabs.
  • Japanese Patent Publication No. 61-44836 discloses a casting nozzle unit using refractories which comprise a primary component consisting of a combination of graphite, and sintered or fused calcia or another ceramic engineering material containing a CaO component.
  • a nozzle unit for use in pouring molten steel from a TD to a mold during casting of steel includes a multi-part type nozzle unit constructed by combining a plurality of segmental nozzles as shown in FIG. 1 , and a single-part type nozzle unit consisting of only a single-piece nozzle as shown in FIG. 2 .
  • the multi-part type nozzle unit is constructed by combining an upper nozzle 2 which is attached to an opening formed in the bottom wall of a tundish 1 , a sliding nozzle 3 , a lower nozzle 4 , and a submerged or immersion nozzle 5 immersed in a mold 6 .
  • the flow rate of molten steel to the mold 6 is controlled by adjusting the opening area of the sliding nozzle 3 .
  • the multi-part type nozzle unit has an excellent flowrate control function, and can stably maintain the level of molten steel.
  • the multi-part type nozzle unit is widely used in view of stable casting performance under constant conditions and excellent safety.
  • the single-part type nozzle unit is comprised of a single elongated immersion nozzle defining a flow path which extends from the bottom opening of the tundish 1 to the mold 6 .
  • the flow rate of molten steel to the mold 6 is controlled by adjusting the area of the bottom opening of the tundish using a long stopper 7 disposed in the tundish 1 .
  • molten steel passing through the nozzle unit has substantially no contact with outside air.
  • outside air enters in the inner hole through joints between the segmental nozzles.
  • outside air inevitably inflows through the joint surface between the sliding nozzle (hereinafter referred to as “SN”) and the associated segmental nozzle, because it is difficult to completely seal the joint surface with the SN to be slidingly moved during use.
  • the molten steel for aluminum-killed steel contains aluminum dissolved therein.
  • the aluminum comes into contact with air, it is oxidized to create alumina.
  • the created alumina becomes incorporated into slabs as alumina inclusions.
  • the multi-part type nozzle unit composed of the plurality of segmental nozzles, even if the CaO-containing refractories are applied to a part of segmental nozzles, alumina will be attached to the remaining segmental nozzles having no CaO-containing refractories, and then large-sized alumina due to agglomeration will be incorporated into slabs.
  • 50% or more of the entire surface area of an inner hole of a nozzle unit to be used for pouring molten steel from a tundish to a mold is formed of refractories containing 20 mass % or more of CaO.
  • the refractories containing 20 mass % or more of CaO are applied to the inner hole of the nozzle unit for allowing molten steel to flow down therethrough, in such a manner that the CaO-containing refractories occupy 50% or more of the entire surface area of the inner hole, the amount of large-size alumina inclusions in obtained slabs is drastically reduced.
  • This effect is derived from a synergistic effect of the actions, of which the CaO-containing refractories act to absorb alumina, a low-melting-point compound created through the reaction between CaO and alumina in the form of a liquid phase acts to smooth the inner hole surface, as well as prevention of the attachment of alumina and prevention of the agglomeration of alumina.
  • Such a synergistic effect can be obtained only if the CaO-containing refractories are applied to the surface of the inner hole of the nozzle unit, in such a manner that they occupy 50% or more of the entire surface area of the inner hole. If the ratio is less than 50%, the action of reducing the amount of alumina flowing into the mold is deteriorated to provide only an insufficient effect of reducing the amount of large-size alumina inclusions in the slabs.
  • the ratio should preferably be set at 60% or more. While 100% of the entire surface area of the inner hole of the nozzle unit may be formed of the CaO-containing refractories, the CaO-containing refractories should be selectively applied to an appropriate region of the nozzle unit in consideration of its use conditions. For example, if a certain region has the risk of causing a problem, such as fusion damage or abrasion, in conjunction with the use of the CaO-containing refractories, suitable conventional refractories for such a region should be used.
  • the present invention can be applied to any multipart type nozzle unit composed of either one of a combination of an upper nozzle and an immersion nozzle, a combination of a SN and an immersion nozzle, a combination of an upper nozzle, a SN and an immersion nozzle, and a combination of an upper nozzle, a SN, an lower nozzle and an immersion nozzle as shown in FIG. 1 , and to any single-part type nozzle unit composed of a single-piece immersion nozzle as shown in FIG. 2 , in such a manner that the CaO-containing refractories occupy 50% or more of the entire surface area of the inner hole of the nozzle unit.
  • the present invention can also be applied to a multi-part type nozzle unit in which a SN is integrated with an upper or lower nozzle in a single piece. Even in case where the CaO-containing refractories are applied to only a portion of the surface of the inner hole of the single-part type nozzle unit, if they are applied to occupy or define 50% or more of the entire surface area of the inner hole of the nozzle unit, the quality of slabs can be significantly improved.
  • the amount of CaO to be contained in the refractories for defining a surface of the inner hole is less than 20 mass %, the refractories have deteriorated abilities of absorbing alumina and preventing the attachment of alumina to provide only an insufficient effect of reducing the amount of large-size alumina inclusions in slabs.
  • the amount of CaO must be 20 mass % or more.
  • the upper limit of the amount of CaO should be appropriately adjusted depending on its use conditions. In usual casting conditions, the amount of CaO may be set at about 60 mass % to obtained sufficient effects.
  • the refractories may include MgO—CaO based refractories, MgO—CaO—C based refractories, ZrO 2 —CaO based refractories, and ZrO 2 —CaO—C based refractories.
  • MgO—CaO based refractories and MgO—CaO—C based refractories are preferable in view of their excellent ability of absorbing alumina.
  • the CaO-containing refractories are essentially applied to at least a surface of the inner hole to be in contact with molten steel.
  • Any region of the nozzle unit other than the inner hole surface may be made of the same material as that of the inner hole surface, or may be made of any suitable refractories used in a conventional nozzle unit.
  • FIG. 1 is a schematic sectional view showing a multi-part type nozzle unit composed of a plurality of segmental nozzles including a SN, which is one example of a nozzle unit to which the present invention is applicable.
  • FIG. 2 is a schematic sectional view showing a single-part type nozzle unit which is another example of a nozzle unit to which the present invention is applicable.
  • FIG. 3 is a graph showing the relationship between the ratio of a surface area of an inner hole of a nozzle unit to be defined by CaO-containing refractories to the entire surface area of the inner hole, and large-size alumina inclusions in obtained slabs.
  • FIG. 4 is a graph showing the relationship between the average amount of CaO in refractories defining a surface area of an inner hole of a nozzle unit, and large-size alumina inclusions in obtained slabs.
  • each of the materials A and B in Table 1 is a CaO-containing material according to the present invention, and each of the materials C and D is a comparative example containing no CaO.
  • Each of the materials A to D was shaped, burnt and machined to prepare sleeve-shaped refractories having a thickness of 10 mm.
  • the sleeve-shaped refractories were inserted into the respective inner holes of the segmental nozzles, and bonded thereto with mortar to form the segmental nozzles as shown in FIG. 1 .
  • the refractories made of the material A or C were applied to the immersion nozzle, and the refractories made of the material B or D were applied to the upper nozzle, the sliding nozzle (SN) and the lower nozzle.
  • Table 2 shows a surface area of the inner hole of each of the segmental nozzles having the CaO-containing refractories applied thereto. TABLE 2 Surface Area of Inner Hole (cm 2 ) Upper Nozzle 393 Sliding Nozzle 438 Lower Nozzle 368 Immersion Nozzle 915
  • a plurality of multi-part type continuous casting nozzle units were prepared by variously combining the prepared segmental nozzles serving as the upper nozzle 2 , SN 3 , lower nozzle 4 and immersion nozzle in FIG. 1 .
  • the influence of the materials used in the nozzle unit on the quality of slabs was experimentally checked to clarify effects derived from the use of the CaO-containing refractories.
  • the casting of aluminum-killed steel was performed while changing a combination of the segmental nozzles under the casting conditions of a ladle volume: 250 ton, a TD volume: 45 ton, and a drawing speed of slabs: 1.0 to 1.3 m/min, and the effects were checked in accordance with the number per area of large-size alumina inclusions having a particle size of 50 ⁇ m or more, which were contained in obtained slabs.
  • Table 3 shows the test result.
  • the number of large-size alumina inclusions in each example is shown by an index number on the basis that the number of large-size alumina inclusions in slabs obtained using the multi-part type nozzle unit in Comparative Example 1 is 100. This means that the nozzle unit having a smaller index number can provide slabs having better quality or a smaller number of large-size alumina inclusions.
  • FIG. 3 diagrammatically shows the result in Table 3 in the form of the relationship between the ratio of a surface area of the inner hole defined by the CaO-containing material to the entire surface area of the inner hole, and the number of large-size alumina inclusions.
  • the ratio of a surface area of the inner hole defined by the CaO-containing refractories to the entire surface area of the inner hole of the nozzle unit is increased up to 50% or more, the number of large-size alumina inclusions is sharply reduced to improve the quality of slabs. Then, the quality of slabs is further improved as the ratio is increased, and the best quality can be obtained when the CaO-containing refractories are applied to the entire surface area of the inner hole of the nozzle unit.
  • Table 4 shows CaO-containing refractories having compositions E to L in addition to the compositions A and B in Table 1.
  • each of these CaO-containing refractories were shaped, burnt and machined to form sleeve-shaped refractories having a thickness of 10 mm.
  • the sleeve-shaped refractories were inserted into the respective inner holes of the segmental nozzles, and bonded thereto with mortar to form segmental nozzles for test.
  • the refractories made of the material A, E, F, G or H were applied to the immersion nozzle 5 in FIG. 1
  • the refractories made of the material B, I, J, K or L were applied to the upper nozzle 2 , the SN 3 , and the lower nozzle 4 in FIG. 1 .
  • a surface area of the inner hole of each of the segmental nozzles is the same as that shown in Table 2.
  • Table 5 The results in Table 5 are summarized in FIG. 4 in the form of the relationship between the average amount of CaO in the refractories applied to the inner hole of the nozzle unit, and the number of large-size alumina inclusions. As seen in FIG. 4 , when the average amount of CaO in the refractories applied to the inner hole of the nozzle unit is increased up to 20 mass % or more, the quality of slabs is significantly improved.
  • the present invention can significantly reduce the amount of large-size inclusions in slabs during casting of aluminum-killed steel, and can be applied to various nozzle units irrespective of nozzle type, such as multi-part type and single-part type.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
  • Continuous Casting (AREA)
  • Compositions Of Oxide Ceramics (AREA)
US10/513,186 2002-04-30 2003-04-30 Nozzle for continuous casting of aluminum killed steel and continuous casting method Abandoned US20050200057A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2002-128337 2002-04-30
JP2002128337A JP4249940B2 (ja) 2002-04-30 2002-04-30 アルミキルド鋼の鋳造方法
PCT/JP2003/005558 WO2003092929A1 (fr) 2002-04-30 2003-04-30 Buse de moulage par coulee continue d'un acier calme a l'aluminium et procede de moulage par coulee continue

Publications (1)

Publication Number Publication Date
US20050200057A1 true US20050200057A1 (en) 2005-09-15

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US10/513,186 Abandoned US20050200057A1 (en) 2002-04-30 2003-04-30 Nozzle for continuous casting of aluminum killed steel and continuous casting method

Country Status (10)

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US (1) US20050200057A1 (ja)
EP (1) EP1504831B1 (ja)
JP (1) JP4249940B2 (ja)
KR (1) KR100835398B1 (ja)
CN (1) CN1305602C (ja)
AU (1) AU2003235985A1 (ja)
BR (1) BR0309646B1 (ja)
DE (1) DE60326948D1 (ja)
MX (1) MXPA04010796A (ja)
WO (1) WO2003092929A1 (ja)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BRPI0413794B1 (pt) * 2003-08-22 2012-01-24 bocal de imersão para lingotamento contìnuo de aço.
BRPI0508726B1 (pt) * 2004-03-15 2013-07-23 bocal de lingotamento contÍnuo
JP4926819B2 (ja) * 2006-05-26 2012-05-09 新日本製鐵株式会社 鋼の連続鋳造方法
BRPI0916819B1 (pt) 2008-07-28 2018-03-06 Nippon Steel & Sumitomo Metal Corporation Material refratário para uma camada intermediária de um bocal de lingotamento contínuo e bocal de lingotamento contínuo
WO2011138831A1 (ja) * 2010-05-07 2011-11-10 黒崎播磨株式会社 耐火物、その耐火物を使用した連続鋳造用ノズル及びその連続鋳造用ノズルの製造方法、並びにその連続鋳造用ノズルを使用した連続鋳造方法
JP6228524B2 (ja) * 2013-09-27 2017-11-08 日新製鋼株式会社 連続鋳造方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4568007A (en) * 1984-01-23 1986-02-04 Vesuvius Crucible Company Refractory shroud for continuous casting
US4691844A (en) * 1986-08-08 1987-09-08 Toshiba Ceramics Co., Ltd. Immersion nozzle for continuous casting
US5100035A (en) * 1989-05-01 1992-03-31 Ferro Corporation Permeable MgO nozzle
US5151201A (en) * 1988-07-01 1992-09-29 Vesuvius Crucible Company Prevention of erosion and alumina build-up in casting elements
US5505348A (en) * 1994-01-25 1996-04-09 Akechi Ceramics Co., Ltd. Molten steel pouring nozzle

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2897893B2 (ja) * 1990-08-09 1999-05-31 明智セラミックス株式会社 連続鋳造用ノズル
JPH04158963A (ja) * 1990-10-19 1992-06-02 Nippon Steel Corp 連続鋳造用ノズル
JPH0780709B2 (ja) * 1991-07-29 1995-08-30 東京窯業株式会社 耐火材料
JPH05154627A (ja) * 1991-08-19 1993-06-22 Shinagawa Refract Co Ltd 非金属介在物付着堆積防止用耐火組成物
JP2706201B2 (ja) 1992-04-13 1998-01-28 黒崎窯業株式会社 連続鋳造用ノズル内孔体
JPH0839214A (ja) 1994-07-30 1996-02-13 Kurosaki Refract Co Ltd 連続鋳造用ノズル
JP2003040672A (ja) * 2001-05-21 2003-02-13 Shinagawa Refract Co Ltd 鋼の連続鋳造耐火部材用耐火物

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4568007A (en) * 1984-01-23 1986-02-04 Vesuvius Crucible Company Refractory shroud for continuous casting
US4691844A (en) * 1986-08-08 1987-09-08 Toshiba Ceramics Co., Ltd. Immersion nozzle for continuous casting
US5151201A (en) * 1988-07-01 1992-09-29 Vesuvius Crucible Company Prevention of erosion and alumina build-up in casting elements
US5100035A (en) * 1989-05-01 1992-03-31 Ferro Corporation Permeable MgO nozzle
US5505348A (en) * 1994-01-25 1996-04-09 Akechi Ceramics Co., Ltd. Molten steel pouring nozzle

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Publication number Publication date
AU2003235985A1 (en) 2003-11-17
BR0309646B1 (pt) 2012-11-27
JP2003320444A (ja) 2003-11-11
KR20050006214A (ko) 2005-01-15
DE60326948D1 (de) 2009-05-14
EP1504831A1 (en) 2005-02-09
EP1504831B1 (en) 2009-04-01
CN1649684A (zh) 2005-08-03
CN1305602C (zh) 2007-03-21
JP4249940B2 (ja) 2009-04-08
WO2003092929A1 (fr) 2003-11-13
BR0309646A (pt) 2005-03-01
EP1504831A4 (en) 2005-08-17
KR100835398B1 (ko) 2008-06-04
MXPA04010796A (es) 2005-07-05

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AS Assignment

Owner name: KROSAKIHARIMA CORPORATION, JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:OGATA, KOJI;SHIMIZU, KOICHI;ASANO, KEISUKE;AND OTHERS;REEL/FRAME:016130/0529;SIGNING DATES FROM 20041115 TO 20041117

Owner name: LWB REGRACTORIES COMPANY, PENNSYLVANIA

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:OGATA, KOJI;SHIMIZU, KOICHI;ASANO, KEISUKE;AND OTHERS;REEL/FRAME:016130/0529;SIGNING DATES FROM 20041115 TO 20041117

AS Assignment

Owner name: KROSAKIHARIMA CORPORATION, JAPAN

Free format text: CORRECTED COVER SHEET TO CORRECT ASSIGNEE NAME, PREVIOUSLY RECORDED AT REEL/FRAME 016130/0529-0533 (ASSIGNMENT OF ASSIGNOR'S INTEREST);ASSIGNORS:OGATA, KOJI;SHIMIZU, KOICHI;ASANO, KEISUKE;AND OTHERS;REEL/FRAME:017178/0147;SIGNING DATES FROM 20041115 TO 20041117

Owner name: LWB REFRACTORIES COMPANY, PENNSYLVANIA

Free format text: CORRECTED COVER SHEET TO CORRECT ASSIGNEE NAME, PREVIOUSLY RECORDED AT REEL/FRAME 016130/0529-0533 (ASSIGNMENT OF ASSIGNOR'S INTEREST);ASSIGNORS:OGATA, KOJI;SHIMIZU, KOICHI;ASANO, KEISUKE;AND OTHERS;REEL/FRAME:017178/0147;SIGNING DATES FROM 20041115 TO 20041117

STCB Information on status: application discontinuation

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