EP0509699A1 - Gasdurchlässiger Giesslochstein - Google Patents

Gasdurchlässiger Giesslochstein Download PDF

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Publication number
EP0509699A1
EP0509699A1 EP92303046A EP92303046A EP0509699A1 EP 0509699 A1 EP0509699 A1 EP 0509699A1 EP 92303046 A EP92303046 A EP 92303046A EP 92303046 A EP92303046 A EP 92303046A EP 0509699 A1 EP0509699 A1 EP 0509699A1
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EP
European Patent Office
Prior art keywords
castable
refractory
porous
gas
refractory material
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.)
Withdrawn
Application number
EP92303046A
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English (en)
French (fr)
Inventor
James D. Engel
Han K. Park
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.)
Vesuvius Crucible Co
Original Assignee
Vesuvius Crucible Co
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 Vesuvius Crucible Co filed Critical Vesuvius Crucible Co
Publication of EP0509699A1 publication Critical patent/EP0509699A1/de
Withdrawn legal-status Critical Current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
    • 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 present invention relates generally to refractory elements used in metallurgical operations and more particularly to an improved well nozzle for use in a tundish, ladle or like vessel in the continuous casting of steel.
  • an inert gas such as argon
  • a porous refractory element in a tundish well nozzle have been recognized, particularly, as an aid in eliminating unwanted inclusions in the steel, preventing air aspiration and in minimizing the deposition of aluminum-type inclusions on the walls of the refractory casting elements. If unchecked, such aluminum oxide depositions will eventually cause complete blockage of the casting element.
  • inert gas introduced to the metal can enters the open annular region and permeates the porous refractory member to exit as a fine dispersion of bubbles in the molten metal stream passing through the axial bore of the well nozzle.
  • the present invention solves the shortcomings of the prior art by providing a porous well nozzle for a metallurgical vessel such as a tundish in which the likelihood of inert gas leakage along the metal can is virtually eliminated.
  • the well nozzle of the invention provides a novel construction in which the inert gas sealing joint is not dependent upon a refractory to metal cement seal, thus eliminating the problem caused by differing thermal expansion coefficients between ceramics and metals, which is inherent in prior art well nozzles.
  • the present invention provides a gas permeable well nozzle which is less expensive to manufacture than prior nozzles because it employs less of the more costly porous refractory material, requires shorter firing times and requires no labor intensive external machining.
  • the present invention is directed to a gas permeable inner nozzle or well nozzle for use in a metallurgical vessel such as in a well block of a tundish.
  • the novel well nozzle is generally cylindrical in shape and includes a gas permeable or porous refractory member having an axial bore therethrough, defining an entry end at an upper end portion and an exit end at a lower end thereof.
  • the porous member is preferably formed of a pressed and fired ceramic refractory material having a high resistance to molten metal erosion such as alumina, zirconia or magnesia, which may be present either as a single phase or as a carbon bonded system.
  • a castable member of a pourable or castable refractory cement material is cast around the outside of the gas permeable member having an open gas annulus defined therebetween.
  • the castable member has upper and lower end portions which extend beyond the gas annulus and directly contact and bond with the outer surfaces of the porous refractory member to form gas impermeable joints along the upper and lower end portions thereof.
  • a transverse gas inlet channel extends through the castable member to communicate at one end with the gas annulus.
  • a metal can, preferably of steel, is positioned around the castable member and includes a gas fitting which communicates with a second end of the gas inlet channel to permit introduction of pressurized inert gas therethrough.
  • the castable refractory member which defines the gas annulus along the porous refractory member forms a very tenacious chemical bond, upon curing, thus, creating a gas impermeable joint between the two refractory members.
  • the major refractory constituents of the porous member and the castable member are identical so as to provide matched thermal expansion rates and thus lessen the opportunity for thermally induced cracking along the gas impermeable joints between the two members.
  • the porous refractory member may be of a pressed and fired alumina material and the castable member may be a mixture of alumina and a cementitious material, preferably consisting of about 95% by weight alumina and about 5% by weight cementitious calcia, plus minor impurities.
  • the predominant hydraulic bonding phase in this system is calcium aluminate.
  • the castable mixture is poured around the porous refractory member with a wax sleeve previously applied on the outer surface of the porous member.
  • the castable portion After drying and moderate temperature curing at about 700°-800°F, the castable portion sets and forms a bond with the gas permeable refractory along the joint areas while the wax sleeve melts and vaporizes to form the open gas annulus in the region formerly occupied by the wax sleeve.
  • compatible matched refractory materials which may be used to form the gas permeable member and castable member also include zirconia and magnesia, wherein the castable member contains preferably about 958 by weight of the matched refractory material and about 58 by weight cement, preferably calcium oxide, plus incidental impurities.
  • the above mentioned refractory materials namely, alumina, zirconia and magnesia may be individually employed in a matched, carbon bonded system for manufacture of both the porous and castable or pourable members.
  • a carbonaceous resin or pitch binder forms a strong carbon bond within and between the respective members.
  • volatile hydrocarbons in the castable or pourable member are driven off during a conventional preheating treatment of the tundish and the member undergoes a further firing treatment during normal use.
  • FIG. 1 shows a partially fragmented section of a conventional tundish 2 which is used in continuous steel casting operations to hold molten metal prior to delivery to a continuous casting machine (not shown).
  • the tundish has a well block area 4 and may include a cylindrical member 6 positioned around the discharge orifice of the tundish for the purpose of improving the quality of the metal being cast therefrom.
  • a conventional well nozzle 8 is cemented into the well block area 4 and contains an axial bore 10 therethrough.
  • a conventional sliding gate valve 12 is fitted to the bottom of the tundish 2 to control the flow of molten metal exiting therefrom.
  • a slideable refractory plate 14 moves between two stationary refractory plates to control the metal flow, all in a well-known manner.
  • a conventional collector nozzle 16 is fitted to the bottom stationary plate of the sliding gate valve 12 and directs the stream of molten metal to a submerged pouring nozzle 18 which, in turn, directs the molten metal to the continuous casting mold (not shown).
  • a conduit 20 supplies pressurized inert gas, such as argon, to the well nozzle 8 for emission as a fine dispersion of inert gas bubbles to the axial bore 10, all of which is well-known in the steelmaking art.
  • a porous well nozzle 8′ is also depicted in Figure 2 and is similar to the nozzle 8 shown in Figure 1.
  • the prior art well nozzle 8′ includes a gas permeable, porous refractory portion 22 of a pressed and fired refractory material, such as alumina, for example.
  • the porous portion 22 is encased by a metal can 24, usually of a steel material.
  • An annular gas slot 26 is defined between the outside surface of the porous refractory portion 22 and the metal can 24.
  • the metal can also includes a threaded fitting 28 which communicates at one end with the annular slot 26 and is adapted to be fitted to an inert gas supply line such as the conduit 20 of Figure 1 to supply pressurized inert gas to the annular slot 26.
  • the steel can 24 is joined to an upper end region of the porous refractory portion 22 by way of a joint 30 formed by a thin layer of refractory cement which creates a barrier to prevent the escape of inert gas from the annular slot 26.
  • a joint 30 formed by a thin layer of refractory cement which creates a barrier to prevent the escape of inert gas from the annular slot 26.
  • the refractory cement joint 30 may begin to fail and thereafter permits the pressurized inert gas to leak from the annular slot 26 along the periphery of the steel can 24.
  • the inert gas will short circuit, taking the path of least resistance and escape around the upper edges of the steel can where the refractory cement 30 has failed.
  • the well nozzle 40 of the invention includes a gas permeable porous refractory member 42 of a generally cylindrical shape with an axial bore 44 formed therethrough. Due to the novel configuration of the present well nozzle 40, the porous refractory member 42 has a smaller wall thickness and diameter than its prior art counterpart depicted in Figure 2, previously identified as porous portion 22. Because of this decrease in physical size, less of the more expensive sized refractory grains are used in the manufacture of the porous member 42 and the time required for firing the refractory is also reduced. Thus, the porous refractory member 42 is less expensive to manufacture than the larger porous portion 22 of the prior art due to decreased material and energy costs.
  • a pourable or castable refractory member 46 having a generally cylindrical shape surrounds the porous refractory member 42.
  • An open gas annulus 48 is positioned intermediate the members 42 and 46 and includes a transverse channel 49 which is adapted to be placed into communication with a remotely positioned supply of pressurized inert gas.
  • the pressurized inert gas fills the annulus 48 and permeates the porous refractory member 42.
  • the gas exits along the sidewall of the axial bore 44 as a fine dispersion of inert gas bubbles in the molten stream of metal passing therethrough.
  • the annulus 48 is formed by the so-called "lost wax” method of casting, well-known in the refractory and foundry arts.
  • a wax sleeve or coating of wax is applied around the outer surface of the fired porous refractory member 42 by hot dipping, for example, to form the gas annulus 48.
  • the upper and lower joint areas 54 and 56 are preferably masked prior to wax application by taping the surface of the porous member 42, which prevents the wax from adhering to these areas.
  • the wax coated piece 42 is then placed in a cylindrical mold having the configuration of the pourable or castable member 46.
  • the tape covering the masked areas 54 and 56 is removed prior to pouring the castable material so as to provide a wax free bonding surface along the upper and lower areas 54 and 56.
  • a wax core is also inserted into the mold in contact with the wax sleeve for formation of the transverse channel 49.
  • the castable or pourable refractory material is poured into the mold and assumes the cylindrical shape of the mold, substantially as depicted in Figure 3.
  • the castable member 46 sets in the mold and assumes a green strength after a given time period after which the green part is dried and then subjected to a thermal curing treatment to harden the castable member 46 and to form the bonded joints 54 and 56.
  • the thermal curing treatment at about 700°-800°F, the previously applied wax melts and volatizes off to produce the open gas annulus 48.
  • a metal closure or can 50 preferably of steel, is positioned around the cured castable member 46 and held in place by a mechanical fit.
  • the can 50 includes a threaded gas conduit fitting 52 which communicates with the transverse channel 49 and is adapted to be attached to an inert gas supply conduit, such as a gas pipe 20 of Figure 1.
  • the gas permeable porous refractory member 42 is constructed of a pressed and fired refractory material such as alumina, zirconia or magnesia, all of which exhibit good erosion resistance in molten steel. After curing, the upper portions of the porous member 42 and castable member 46 form a high strength bonded joint 54 along their interface. A similar strong bonded joint 56 is formed along the lower portions of the contacting surfaces of the porous member 42 and castable member 46.
  • the porous member 42 is made from a refractory material selected from alumina, zirconia or magnesia.
  • the porous member is pressed and fired all in a well-known manner.
  • the castable member 46 is constructed of a matched refractory system containing a high percentage of one of alumina, zirconia or magnesia plus, a small percentage of a refractory cement component.
  • a preferred dry mix ratio for the castable member is about 95% by weight refractory material and about 5% by weight cement, preferably calcium oxide cement.
  • the use of like refractory materials in the members 42 and 46 provides matched thermal expansion rates in the porous and castable members.
  • Such matched thermal expansion properties serves to maintain the integrity of the gas impermeable joints 54 and 56 during service and prevents cracking and subsequent leakage of inert gas therebetween.
  • the joint provided by the cementitious material in the castable member 46 creates a strong bond with the refractory material of the porous refractory member 42.
  • the resulting joints 54 and 56 are much stronger than the prior art joint 30 between the refractory cement and the metal can.
  • the close matching of thermal expansion rates of the members 42 and 46 provides further resistance to thermally induced cracking at the bonded joints 54 and 56.
  • castable member 46 is poured around the porous member 42, there is no need for time consuming and costly machining operations to fit the parts together as previously called for in the prior art.
  • the castable refractory mixture making up member 46 in the wet, unset condition is flowable and conforms to any surface irregularities which may be present on the outer surface of the porous member 42.
  • the wax sleeve employed to form the open gas annulus 48 likewise accommodates any surface imperfections or irregularities which may be present on the outer surface of the member 42.
  • the present invention also contemplates the use of matched carbon bonded refractory systems, in which case the previously described cementitious constituent in the castable member 46 is not used.
  • a resin or pitch carbonaceous binder in an amount of between about 2%-30% by weight is preferably employed in the refractory mix and formulated as a pourable material which is cast into place around a like carbon bonded refractory porous member 42 which has been previously pressed and fired.
  • Refractory systems such as carbon bonded alumina, carbon bonded zirconia and carbon bonded magnesia are well-known in the art and provide good steel erosion resistance and superior thermal shock resistance.
  • the carbon bonded refractory systems also form strong joints 54 and 56 as previously described.
  • the metal can 50 holds the unfired, pourable carbon bonded refractory in place and prevents handling damage to the pourable member 46 prior to thermal treatment which occurs during use.
  • the volatile hydrocarbon materials are driven off from the pourable member 46 such that the member 46 is cured as the tundish is preheated prior to start-up of metal teeming.
  • the much higher temperatures which occur during continuous steel casting then provide a further firing treatment to the carbon bonded refractory pourable member 46.
  • Such carbon bonded refractories also exhibit improved, longer life inert gas sealing along the joints 54 and 56 due to the fact that the refractories employed in the carbon bonded systems are matched. Therefore, the previously discussed balanced thermal expansion and contraction properties between the porous refractory member 42 and the pourable refractory 46 are likewise achieved in the carbon bonded refractories.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Continuous Casting (AREA)
  • Carbon Steel Or Casting Steel Manufacturing (AREA)
EP92303046A 1991-04-12 1992-04-07 Gasdurchlässiger Giesslochstein Withdrawn EP0509699A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US68507491A 1991-04-12 1991-04-12
US685074 1991-04-12

Publications (1)

Publication Number Publication Date
EP0509699A1 true EP0509699A1 (de) 1992-10-21

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ID=24750678

Family Applications (1)

Application Number Title Priority Date Filing Date
EP92303046A Withdrawn EP0509699A1 (de) 1991-04-12 1992-04-07 Gasdurchlässiger Giesslochstein

Country Status (4)

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EP (1) EP0509699A1 (de)
KR (1) KR920019452A (de)
BR (1) BR9201325A (de)
CA (1) CA2064392A1 (de)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0771601A1 (de) * 1995-10-31 1997-05-07 Richard Dudley Shaw Feuerfeste Giessdüse
EP0982088A1 (de) * 1998-07-31 2000-03-01 LTV Steel Company, Inc. Verhinderung von Gussblasen in Stahl
RU2172228C2 (ru) * 1995-10-10 2001-08-20 Визувиус Крусибл Компани Сопловой узел с распределителем инертного газа
WO2008096954A1 (en) * 2007-02-07 2008-08-14 Wonjin Worldwide Co., Ltd. Preparation of refractory for making steel ingots
JP2017196643A (ja) * 2016-04-27 2017-11-02 黒崎播磨株式会社 下部ノズル
CN107745081A (zh) * 2017-11-22 2018-03-02 扬州峰明光电新材料有限公司 U形镁合金件的差压浇注系统及差压浇注方法
KR20210102750A (ko) 2020-02-12 2021-08-20 주식회사 포스코 웰 블록, 주조 장치 및 방법
WO2023047153A1 (en) * 2021-09-24 2023-03-30 Arcelormittal Leak-proof upper tundish nozzle

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107225231B (zh) * 2017-07-14 2022-09-02 山东钢铁股份有限公司 一种连铸中间包环形气幕挡墙及其安装方法
CN108705073A (zh) * 2018-06-06 2018-10-26 仙居县顺安交通设施有限公司 铁水浇注装置

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1492534A (en) * 1974-11-04 1977-11-23 Flogates Ltd Pouring of metals
GB1575602A (en) * 1977-01-13 1980-09-24 Didier Werke Ag Refractory structures for outlet valves for metallurgical vessels
JPS5762857A (en) * 1980-09-29 1982-04-16 Kurosaki Refract Co Ltd Production of nozzle for casting having slit
JPS59113962A (ja) * 1982-12-21 1984-06-30 Harima Refract Co Ltd 溶鋼鋳造用ノズルの製造方法
WO1984002670A1 (en) * 1983-01-03 1984-07-19 Vesuvius Crucible Co Flow control nozzle for continuous casting
US4691844A (en) * 1986-08-08 1987-09-08 Toshiba Ceramics Co., Ltd. Immersion nozzle for continuous casting

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1492534A (en) * 1974-11-04 1977-11-23 Flogates Ltd Pouring of metals
GB1575602A (en) * 1977-01-13 1980-09-24 Didier Werke Ag Refractory structures for outlet valves for metallurgical vessels
JPS5762857A (en) * 1980-09-29 1982-04-16 Kurosaki Refract Co Ltd Production of nozzle for casting having slit
JPS59113962A (ja) * 1982-12-21 1984-06-30 Harima Refract Co Ltd 溶鋼鋳造用ノズルの製造方法
WO1984002670A1 (en) * 1983-01-03 1984-07-19 Vesuvius Crucible Co Flow control nozzle for continuous casting
US4691844A (en) * 1986-08-08 1987-09-08 Toshiba Ceramics Co., Ltd. Immersion nozzle for continuous casting

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 6, no. 142 (M-146)(1020) 31 July 1982 & JP-A-57 062 857 ( KUROSAKI YOUGIYOU KK ) 16 April 1982 *
PATENT ABSTRACTS OF JAPAN vol. 8, no. 234 (M-334)(1671) 26 October 1984 & JP-A-59 113 962 ( HARIMA TAIKA RENGA KK ) 30 June 1984 *

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2172228C2 (ru) * 1995-10-10 2001-08-20 Визувиус Крусибл Компани Сопловой узел с распределителем инертного газа
EP0771601A1 (de) * 1995-10-31 1997-05-07 Richard Dudley Shaw Feuerfeste Giessdüse
US5744050A (en) * 1995-10-31 1998-04-28 Shaw; Richard Dudley Nozzle
EP0982088A1 (de) * 1998-07-31 2000-03-01 LTV Steel Company, Inc. Verhinderung von Gussblasen in Stahl
WO2008096954A1 (en) * 2007-02-07 2008-08-14 Wonjin Worldwide Co., Ltd. Preparation of refractory for making steel ingots
JP2017196643A (ja) * 2016-04-27 2017-11-02 黒崎播磨株式会社 下部ノズル
CN107745081A (zh) * 2017-11-22 2018-03-02 扬州峰明光电新材料有限公司 U形镁合金件的差压浇注系统及差压浇注方法
KR20210102750A (ko) 2020-02-12 2021-08-20 주식회사 포스코 웰 블록, 주조 장치 및 방법
WO2023047153A1 (en) * 2021-09-24 2023-03-30 Arcelormittal Leak-proof upper tundish nozzle

Also Published As

Publication number Publication date
BR9201325A (pt) 1992-12-01
KR920019452A (ko) 1992-11-19
CA2064392A1 (en) 1992-10-13

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