US20120217271A1 - Molten metal discharge nozzle - Google Patents

Molten metal discharge nozzle Download PDF

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Publication number
US20120217271A1
US20120217271A1 US13/496,272 US201013496272A US2012217271A1 US 20120217271 A1 US20120217271 A1 US 20120217271A1 US 201013496272 A US201013496272 A US 201013496272A US 2012217271 A1 US2012217271 A1 US 2012217271A1
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US
United States
Prior art keywords
bore
radius
nozzle
molten steel
wall surface
Prior art date
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Abandoned
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US13/496,272
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English (en)
Inventor
Arito Mizobe
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.)
Krosaki Harima Corp
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Krosaki Harima Corp
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Filing date
Publication date
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Assigned to KROSAKIHARIMA CORPORATION reassignment KROSAKIHARIMA CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: MIZOBE, ARITO
Publication of US20120217271A1 publication Critical patent/US20120217271A1/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
    • 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
    • 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
    • B22D46/00—Controlling, supervising, not restricted to casting covered by a single main group, e.g. for safety reasons

Definitions

  • the present invention relates to a molten metal discharge nozzle designed to be installed in a bottom of a molten metal vessel to discharge molten metal from the molten metal vessel, and configured such that it has in an axial direction thereof a bore for allowing passage of molten metal,.
  • alumina and other inclusions are apt to adhere to a wall surface of a bore of the upper nozzle for allowing passage of molten metal to form an adhesion matter thereon, which narrows a flow passage to hinder a casting operation, or is likely to fully clog the flow passage to preclude the casting operation.
  • a method has been proposed which is intended to provide a gas injection port to inject an inert gas (see, for example, the following Patent Document 1 or 2).
  • an upper nozzle disclosed in the Patent Document 1 or 2 has a complicated structure which requires time-consuming fabrication, and it is necessary to supply gas during a casting operation, which leads to an increase in cost. Moreover, even if the gas injection-type nozzle is employed, it is difficult to completely prevent the occurrence of the adhesion matter.
  • a widely used type of upper nozzle includes, for example, a type consisting of a reverse taper region formed on an upper(upstream) side thereof and a straight region formed on a lower(downstream) side thereof (see FIG. 8( a )), and a type having an arc-shaped region continuously extending from the reverse taper region and the straight region (see FIG. 9( a )).
  • a type consisting of a reverse taper region formed on an upper(upstream) side thereof and a straight region formed on a lower(downstream) side thereof see FIG. 8( a )
  • a type having an arc-shaped region continuously extending from the reverse taper region and the straight region see FIG. 9( a )
  • each diagram suffixed by (a) illustrates an upper nozzle under the condition that it is installed in a sliding nozzle device (hereinafter referred to as “SN device”), wherein a region downward (downstream) of the one-dot chain line is a bore of an upper plate, and a region downward of a position where two bores are out of alignment is a bore of an intermediate plate or a lower plate.
  • SN device sliding nozzle device
  • a distribution of pressures to be applied to a wall surface of a bore in an upper nozzle (length: 230 mm) having the configuration illustrated in FIG. 8( a ) during passage of molten steel through the bore was calculated (by computer simulation-based fluid analysis). As a result, it was ascertained that the pressure is rapidly changed in a region beyond a position (away from an upper(upstream) end of the bore by 180 mm) where the bore wall surface is changed from a reverse taper configuration to a straight configuration, as indicated by the dotted line in FIG. 8( b ).
  • the computer simulation-based fluid analysis was performed using fluid analysis software (trade name “Fluent Ver. 6.3.26 produced by Fluent Inc.).
  • Input parameters in the fluid analysis software are as follows:
  • the rapid pressure change and the arc-curved pressure change are caused by a phenomenon that a molten steel flow is changed along with a change in configuration of the bore wall surface from the reverse taper configuration to the straight configuration.
  • a swirling nozzle adapted to intentionally change a molten steel flow, an adhesion matter is observed around a position where the molten steel flow is changed.
  • an adhesion matter on the bore wall surface can be suppressed by creating a smooth molten steel flow, i.e., a molten steel flow having an approximately constant pressure change with respect to the bore wall surface.
  • Patent Document 3 As a technique for stabilizing a molten steel flow, an invention concerning a configuration of a bore of a tapping tube for a converter has been proposed (see, for example, the following Patent Document 3).
  • a technique disclosed in the Patent Document 3 is intended to prevent a vacuum area from being formed in a central region of a molten steel flow so as to suppress entrapment of slag and incorporation of oxygen, nitrogen, etc., but it is not intended to prevent the occurrence of the adhesion matter. Further, the technique disclosed in the Patent Document 3 is designed for a converter(refining vessel), wherein the effect of preventing entrapment of slag, etc., becomes important in a last stage of molten steel discharge (assuming that a tapping time is 5 minutes, the last stage is about 1 minute).
  • Patent Document 1 JP 2007-090423A
  • Patent Document 2 JP 2005-279729A
  • Patent Document 3 JP 2008-501854A
  • the present invention provides a molten metal discharge nozzle having in an axial direction thereof a bore for allowing passage of molten metal, wherein: a radius r(0) of an upper end of the bore is 1.5 times or more a radius r(L) of a lower end of the bore; a line indicative of a wall surface of the bore in a cross-section taken along an axis of the bore has no bend point; a radius r(1 ⁇ 4 L) of the bore at a position downwardly away from the upper end of the bore by a distance of 1 ⁇ 4 L (where L is an axial length of the bore) is in a range between [[L/ ⁇ (r(0)/r(L)) 1.5 ⁇ 1 ⁇ +L]/[L ⁇ r(0)/r(L)) 1.5 ⁇ 1 ⁇ +1 ⁇ 4 L]] 1/1.5 ⁇ r(L) and [[L/ ⁇ (r(0)/r(L)) 6 ⁇ 1 ⁇ +L]/[L/ ⁇ (r(0)/r(L)) 6 ⁇ 1 ⁇
  • the molten metal discharge nozzle of the present invention can suppress the occurrence of an adhesion matter on the wall surface of the bore during passage of molten metal therethrough.
  • FIG. 1 is a vertical cross-sectional view illustrating one example of an upper nozzle according to the present invention.
  • FIGS. 8( a ) and 8 ( b ) are, respectively, a diagram illustrating a configuration of a conventional upper nozzle, and a graph illustrating a pressure distribution during passage of molten steel through the conventional upper nozzle.
  • FIGS. 9( a ) and 9 ( b ) are, respectively, a diagram illustrating a configuration of a conventional upper nozzle, and a graph illustrating a pressure distribution during passage of molten steel through the conventional upper nozzle.
  • FIG. 10 is a schematic axial cross-sectional view illustrating a tundish and an upper nozzle.
  • FIG. 11 shows Table 1.
  • FIG. 12 shows Table 2.
  • FIG. 13 shows Table 3.
  • the present invention will now be specifically described based on an embodiment thereof by taking an upper nozzle as an example.
  • FIG. 1 is a cross-sectional view illustrating one example of an upper nozzle according to the present invention, taken along an axial direction of a bore thereof for allowing passage of molten steel.
  • an upper nozzle 10 according to the present invention is formed with a bore 11 for allowing passage of molten steel, wherein the bore has a large-diameter end 12 adapted to be fitted into a discharge opening of a tundish or a ladle, a small-diameter end 13 adapted to discharge molten steel therefrom, and a bore wall surface 14 continuously extending from the large-diameter end 12 to the small-diameter end 13 .
  • the upper nozzle 10 is configured such that a radius r(0) of an upper end (large-diameter end 12 ) of the bore is 1.5 times or more a radius r(L) of a lower end (small-diameter end 13 ) of the bore, and a line indicative of the bore wall surface 14 in a cross-section taken along an axis of the bore 11 has no bend point.
  • a radius r(1 ⁇ 4 L) of the bore 11 at a position downwardly away from the upper end of the bore by a distance of 1 ⁇ 4 L, a radius r(1 ⁇ 2 L) of the bore at a position downwardly away from the upper end of the bore by a distance of 1 ⁇ 2 L, and a radius r(3/4) of the bore at a position downwardly away from the upper end of the bore by a distance of 3 ⁇ 4 L are, respectively, in a range between [[L/ ⁇ (r(0)/r(L)) 1.5 ⁇ 1 ⁇ +L]/[L ⁇ r(0)/r(L)) 1.5 ⁇ 1 ⁇ +1 ⁇ 4 L]] 1/1.5 ⁇ r(L) and [[L/ ⁇ (r(0)/r(L)) 6 ⁇ 1 ⁇ +L]/[L/ ⁇ (r(0)/r(L)) 6 ⁇ 1 ⁇ +1 ⁇ 4 L]] 1/6 ⁇ r(L), a range between [[L/[L/ ⁇ (r(0)/r(L)) 1.5
  • a curve (line) indicated by the reference numeral 15 is a locus of a radius r(z) represented by the following formula:
  • a curve (line) indicated by the reference numeral 16 is a locus of a radius r(z) represented by the following formula:
  • the present invention requires that: each of three radii r(1 ⁇ 4 L), r(1 ⁇ 2 L), r(3 ⁇ 4) of the bore at respective points by which the axial length L of the bore is divided into quarters falls within a range between the curve 15 and the curve 16 ; and the line indicative of the bore wall surface 14 in a cross-section taken along the axis of the bore 11 has no bend point.
  • a flow velocity v (z) of molten steel at a position away from an upper end of the bore by a distance z is expressed as follows:
  • g is a gravitational acceleration
  • a flow volume Q of molten steel flowing through the bore of the upper nozzle is a product of a flow velocity v of the molten steel and a cross-sectional area A of the bore.
  • the flow volume Q is expressed as follows:
  • L is a length of the bore (a length of the upper nozzle);
  • a cross-sectional area A(z) at a position away from the upper end of the bore by a distance z is expressed as follows:
  • a radius r(z) of the bore at an arbitrary position is expressed as follows:
  • the bore is configured such that the radius r(z) thereof at an arbitrary position satisfies the Formula 1, so that a pressure applied onto the bore wall surface is reduced gradually and gently in a downward direction from the upper end of the nozzle (upper end of the bore) to provide a low-energy less, smooth and straightened molten steel flow.
  • the above formula for calculating the pressure distribution using the H′ is set up on an assumption that molten steel flows into the upper end of the bore directly and uniformly in an approximately vertical direction according to a hydrostatic head pressure of a molten steel bath in the tundish.
  • multi-directional flows of molten steel are formed from the vicinity of a bottom surface of the tundish adjacent to the upper end of the nozzle serving as an inlet of a molten steel discharge passage, toward the bore, as described above.
  • the inventers carried out studies based on various simulations. As a result, the inventers found out that it is effective to use a value of the H′ to be obtained when zero is assigned to z in the Formula 1, as a hydrostatic head height H for the calculation, i.e., calculational hydrostatic head height H (hereinafter referred to simply as “H”, on a case-by-case basis).
  • H calculational hydrostatic head height
  • the H can be expressed as follows:
  • the H is defined by a ratio between the radius r( 0 ) of the bore at the upper end of the nozzle and the radius r(L) of the bore at the lower end of the nozzle, and the axial length L of the bore.
  • This calculational hydrostatic head height H has an influence on a pressure of molten steel within the bore of the nozzle of the present invention.
  • a cross-sectional shape of the bore wall surface calculated using the H in place of the H′ in the Formula 1 makes it possible to suppress a rapid pressure change which would otherwise occur adjacent to the upper end of the bore.
  • the Formula 2 can be transformed as follows:
  • FIG. 10 is a schematic axial cross-sectional view illustrating a tundish and an upper nozzle, wherein the upper end of the bore is an origin (zero point) of the distance z.
  • the inventors have found out that the rapid pressure change which would otherwise occur adjacent to the upper end of the bore can be suppressed by setting the radius r(0) of the upper end of the bore to be 1.5 times or more the radius r(L) of the lower end of the bore. This is because, if the radius r(0) of the upper end of the bore is less than 1.5 times the radius r(L) of the lower end of the bore, it becomes difficult to sufficiently ensure a distance for smoothing a configuration from the tundish or ladle to the upper nozzle, so that the configuration is rapidly changed.
  • the radius r(0) of the upper end of the bore is equal to or less than 2.5 times the radius r(L) of the lower end of the bore, because a discharge opening of the tundish or ladle will be unrealistically increased along with an increase in the radius r(0) of the upper end of the bore.
  • variable n is applied to the Formula 3 to express the calculational head height H as follows:
  • the radius r(z) of the bore at a position downwardly away from the upper end of the bore by an arbitrary distance z is expressed by the Formula 6.
  • FIG. 2( b ) illustrates a result of the calculation on an assumption that a pressure to be applied onto a wall surface at an upper end of a bore of an upper nozzle illustrated in FIG. 7 as a conventional upper nozzle is zero.
  • the pressure is largely changed from about 100 Pa in the upper end region of the bore, as illustrated in FIG. 5 .
  • a pressure greater than that in the conventional upper nozzle ( FIG. 7 ) occurs in the upper end region of the bore, and subsequently the pressure is extremely largely changed.
  • the radius of the bore is sharply reduced in the upper end region of the bore, and the molten steel flow is rapidly changed in an area where the bore is narrow and therefore an adhesion matter is more likely to cause a problem.
  • a change in pressure to be applied to the bore wall surface is approximately constant during passage of molten steel through the bore of the upper nozzle, i.e., the molten steel flow is a low-energy loss and stabilized flow.
  • a molten-steel level in a ladle will be gradually lowered from about 4000 mm, and a molten-steel level in some tundishes is about 500 mm.
  • molten metal flowing into the discharge opening is molten metal located adjacent to the bottom surface of the tundish or ladle.
  • the pressure distribution has the same characteristic as those in the inventive and comparative examples.
  • the inventors carried out a study on a smooth nozzle in which no corner(bend point) is formed in a bore wall surface thereof, i.e., a nozzle in which a curve in a vertical cross-section of a bore thereof is formed as a curve of continuous differential values of r(z) with respect to z, i.e., (d(r(z))/dz).
  • the inventors carried out a study on an upper nozzle in which a curve in a vertical cross-section of a bore thereof is smooth but it does not conform to that according to the Formula 6, using, as criteria, three points by which the axial length L of the bore is divided into quarters.
  • a smooth bore configuration having no bend point is substantially determined by specifying total five points consisting of the upper and lower ends of the bore and the above three points.
  • a result of the evaluation is illustrated in Table 2, FIG. 12 .
  • the inventors carried out a study on a relationship between a distribution of pressures to be applied onto a bore wall surface of an upper nozzle, and an inner diameter ratio of an upper end to a lower end of a bore of the upper nozzle.
  • a molten steel flow can be stabilized to suppress the occurrence of an adhesion matter by providing a smooth cross-sectional configuration of a bore wall surface having no corner(bend point), i.e., a cross-sectional configuration based on continuous differential values of r(z) with respect to z, i.e., (d(r(z))/dz), wherein the radius r(z) of the bore it is in a rage between [[L/ ⁇ (r(0)/r(L)) 1.5 ⁇ 1 ⁇ +L]/[L/ ⁇ r((0)/r(L)) 1.5 ⁇ 1 ⁇ +z]] 1/1.5 ⁇ r(L) and [[L/ ⁇ (r(0)/r(L)) 6 ⁇ 1 ⁇ +L]/[L/ ⁇ r((0)/r
  • a configuration of an upper end region of the bore is likely to be determined by a factor such as a configuration of a stopper. Further, the upper end region of the bore has a relatively large inner diameter, so that it is less likely to be affected by an adhesion matter.
  • a configuration of a lower end region of the bore is likely to be determined in connection with production conditions. For example, in some cases, it has to be formed in a straight bore to allow a core or the like to be inserted thereinto during production.
  • the lower end region of the bore is formed in a configuration close to a straight bore, so that an influence on an anti-adhesion matter effect is small. Therefore, the cross-section of the bore wall surface may be formed in a configuration having no bend point, except the upper end and lower end regions of the bore.
  • a bubbling mechanism for injecting an inert gas, such as Ar gas may be used in combination.
  • the molten metal discharge nozzle of the present invention is not limited to an upper nozzle, but the present invention may be applied to any other nozzle, such as an open nozzle, to be installed to a vessel, such as a tundish having an approximately constant hydrostatic head height of molten metal.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Continuous Casting (AREA)
  • Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
US13/496,272 2009-09-16 2010-06-02 Molten metal discharge nozzle Abandoned US20120217271A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2009-214718 2009-09-16
JP2009214718A JP2011062722A (ja) 2009-09-16 2009-09-16 溶融金属排出用ノズル
PCT/JP2010/059308 WO2011033829A1 (ja) 2009-09-16 2010-06-02 溶融金属排出用ノズル

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US20120217271A1 true US20120217271A1 (en) 2012-08-30

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US13/496,272 Abandoned US20120217271A1 (en) 2009-09-16 2010-06-02 Molten metal discharge nozzle

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US (1) US20120217271A1 (ja)
EP (1) EP2478980A4 (ja)
JP (1) JP2011062722A (ja)
KR (1) KR20120062876A (ja)
CN (1) CN102497947B (ja)
AU (1) AU2010296717B2 (ja)
BR (1) BR112012005717A2 (ja)
CA (1) CA2771823A1 (ja)
TW (1) TW201111518A (ja)
WO (1) WO2011033829A1 (ja)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5156141B1 (ja) * 2012-07-13 2013-03-06 黒崎播磨株式会社 上ノズルの使用方法
JP5912193B1 (ja) * 2015-01-23 2016-04-27 株式会社クボタ ノズル構造、鋳造機、および鋳造物の製造方法

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2341859A (en) * 1939-07-04 1944-02-15 Weyerhacuser Timber Company Nozzle
AT387039B (de) * 1981-02-05 1988-11-25 Veitscher Magnesitwerke Ag Abstichvorrichtung fuer konverter
US4510191A (en) * 1982-09-30 1985-04-09 Toshiba Ceramics Co., Ltd. Casting nozzle
DE3706694A1 (de) * 1987-03-02 1988-09-15 Lechler Gmbh & Co Kg Zweistoff-zerstaeubungsduese zur erzeugung eines vollkegelstrahls
JPH0686850U (ja) * 1993-05-27 1994-12-20 新日本製鐵株式会社 タンディッシュ用ストッパー
JPH0716715A (ja) * 1993-07-06 1995-01-20 Nippon Steel Corp 溶湯注入ノズル
US5452827A (en) * 1993-07-13 1995-09-26 Eckert; C. Edward Nozzle for continuous caster
JP3639513B2 (ja) * 2000-08-28 2005-04-20 黒崎播磨株式会社 オープンノズル
JP4277999B2 (ja) 2004-03-30 2009-06-10 明智セラミックス株式会社 タンディッシュ上ノズル
DE102004027440B3 (de) 2004-06-04 2005-06-16 Refractory Intellectual Property Gmbh & Co. Kg Abstichrohr
JP4818675B2 (ja) 2005-09-30 2011-11-16 Ｊｆｅスチール株式会社 連続鋳造設備の上ノズル

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TW201111518A (en) 2011-04-01
WO2011033829A1 (ja) 2011-03-24
CN102497947B (zh) 2014-02-26
KR20120062876A (ko) 2012-06-14
AU2010296717B2 (en) 2013-04-04
CN102497947A (zh) 2012-06-13
EP2478980A1 (en) 2012-07-25
BR112012005717A2 (pt) 2016-02-23
CA2771823A1 (en) 2011-03-24
AU2010296717A1 (en) 2012-04-12
EP2478980A4 (en) 2017-11-29
JP2011062722A (ja) 2011-03-31

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Owner name: KROSAKIHARIMA CORPORATION, JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:MIZOBE, ARITO;REEL/FRAME:028217/0308

Effective date: 20120402

STCB Information on status: application discontinuation

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