EP0342020A2 - Procédé et dispositif de coulée de bande de métal - Google Patents

Procédé et dispositif de coulée de bande de métal Download PDF

Info

Publication number
EP0342020A2
EP0342020A2 EP89304760A EP89304760A EP0342020A2 EP 0342020 A2 EP0342020 A2 EP 0342020A2 EP 89304760 A EP89304760 A EP 89304760A EP 89304760 A EP89304760 A EP 89304760A EP 0342020 A2 EP0342020 A2 EP 0342020A2
Authority
EP
European Patent Office
Prior art keywords
cooling wall
strip
oscillating
zone
metal
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Withdrawn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
EP89304760A
Other languages
German (de)
English (en)
Other versions
EP0342020A3 (fr
Inventor
Robert F. Hunter
Raymond L. Lapointe
John C. Mckay
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.)
Stelco Inc
Original Assignee
Stelco Inc
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 Stelco Inc filed Critical Stelco Inc
Publication of EP0342020A2 publication Critical patent/EP0342020A2/fr
Publication of EP0342020A3 publication Critical patent/EP0342020A3/fr
Withdrawn legal-status Critical Current

Links

Images

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
    • 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
    • B22D11/04—Continuous casting of metals, i.e. casting in indefinite lengths into open-ended moulds
    • B22D11/053—Means for oscillating the moulds
    • B22D11/0535—Means for oscillating the moulds in a horizontal plane
    • 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
    • B22D11/14—Plants for continuous casting

Definitions

  • This invention relates generally to a method and apparatus for producing thin steel slabs and strip, and has to do particularly with a process by which such materials can be directly cast.
  • One conventional method of making steel strip is to use the well known continuous casting process to make slabs which may typically be 200 mm to 250 mm thick. These slabs are then put through a hot strip mill where they are rolled down to a thickness of typically 1.8 to 4.8 mm, whereupon they are passed through a cold finishing mill to achieve the final thickness.
  • a significant departure from the twin roll casting concept is represented by Japanese patent application 2230458, assigned to Nippon Steel Corp.
  • a container with an open top is defined by a sloping bottom wall and a weir (lateral wall) extending around three sides.
  • the bottom wall is water-­cooled and receives the input of high-frequency vibratory energy to reduce friction.
  • Hot metal is poured into the basin so defined, and solidifies as a layer against the cooled bottom wall. This layer is then withdrawn through the missing fourth wall, coming off as a strip which passes between one or more pairs of nip rollers.
  • a major disadvantage of this Japanese development is the fact that the melt has its top surface exposed to the air. Moreover, in the region where the strip is exiting from the continuous casting mold, the upper surface of the molten steel literally "becomes" the top surface of the final cast product. This is very disadvantageous due to the fact that the upper surface of the melt tends to become covered with slag, flux or oxides which are undesirable as inclusions in the top surface of the finished strip. Additionally there are certain fluid flow problems associated with trying to cast from a liquid surface, problems that can contribute to a rough (wavy) solidified surface.
  • this invention provides an apparatus for the manufacture of metal strip, comprising: a primary solidification zone in the form of a chamber for containing molten metal, the chamber being defined in part by an oscillating cooling wall upon which solidification of the molten metal can take place, thus creating one face of the metal strip, first cooling means for withdrawing heat from said cooling wall, a secondary solidification zone adjoining the primary solidification zone and adapted to receive solidified metal from said primary zone, the secondary solidification zone being defined in part by a further cooling wall facing oppositely from said oscillating cooling wall, whereby solidification of the molten metal can take place against the further cooling wall to create a second face of the metal strip, the secondary solidification zone including means for maintaining the metal strip juxtaposed against said further cooling wall, second cooling means for withdrawing heat from said further cooling wall, and extracting means for withdrawing the metal strip from said primary zone through said secondary zone.
  • this invention provides a method for the continuous manufacture of metal strip at or near the desired final thickness, the method comprising the steps: metering molten metal into a primary solidification zone in the form of a chamber, the chamber being defined in part by a cooling wall, withdrawing heat from said cooling wall so that the metal solidifies in a layer against the cooling wall, thus creating one face of the metal strip, oscillating said cooling wall to discourage the solidified metal from adhering to the cooling wall, passing the layer of solidified metal into a secondary solidification zone adjoining the primary solidification zone, the secondary solidification zone being defined in part by a further cooling wall facing oppositely from said first-mentioned cooling wall, so that solidification of the molten metal takes place against the further cooling wall to create a second face of the metal strip, maintaining the metal strip juxtaposed against said further cooling wall to avoid break-out of molten metal from said chamber, and withdrawing the metal strip from said secondary zone.
  • Figure 1 shows a ladle 10 delivering molten steel to a tundish 12. From the tundish 12 the molten steel passes to a strip casting mold 14 which will be described in greater detail later in this specification.
  • the strip casting mold 14 continuously casts a steel strip which passes through a housing 16, and then through a plurality of rollers 18 which re-direct the strip into a horizontal direction.
  • a laminar spray cooling mechanism 20 is provided to reduce the temperature of the strip, and finally the strip is coiled in a coiling facility 22.
  • Figure 2 illustrates the details of construction for one embodiment of a strip casting mold 14.
  • An internal chamber 24 has an open top end 26, and is defined between a substantially vertical face 28, substantially vertical insulating side walls 30 (only one seen in the sectional view of Figure 2), and an insulating oblique wall 32. Near the top of the mold 14, the oblique wall 32 joins a short vertical wall 34.
  • the walls 32 and 34 are surfaces of a monolithic refractory block 36 which is held in place by frame members 38, bottom support panel 39, and vertical panel 40.
  • the vertical face 28, in the embodiment illustrated, is the inside face of a panel 43 which is preferably of high-conductivity copper.
  • the panel 43 constitutes a cooling wall which is coated with boron nitride due to the "slippery" nature of this material with respect to solidified steel. While boron nitride is considered to be a preferred low-friction material that could be advantageously used in this invention, it is emphasized that other materials with similar properties could be selected, and the present invention should not be considered limited to this particular material.
  • the panel 43 is part of a complex geometry which includes horizontal integral fins 50.
  • the fins 50 are spaced apart vertically, and define chambers into which cooling water can be sprayed from a plurality of appropriately positioned nozzles 52 connected to pipes 54.
  • the complex of which panel 43 forms a part includes side walls 56 (only one being seen in the vertical sectional view of Figure 2).
  • the panel 43 does not extend the full height of the wall.
  • the panel 43 is connected to a top wall 60 which defines the bottom extremity of an insulation chamber 62 in which insulation is provided.
  • the top of the chamber 62 is defined by a plate 64.
  • the insulation provided in chamber 62 may be alumina or an alumina-graphite composite. Such insulation may be coated on the inside face 65a with a material such as zirconia (Zr2O3).
  • Panel 43 is integral at the bottom with a flange 60a that rests on a plate 64a. Structures 65 are shown schematically to represent support means for the strip caster.
  • the intended level for the molten steel is at the line 66, this line being above the upper wall 60 of the cooling unit.
  • the upper layers of the melt remain at a high temperature and do not contribute material to the forming strip.
  • the solidification thus begins at some chosen depth below the surface of the melt but still proceeds against a continuous integral face.
  • a further cooling wall 68 spaced leftwardly away from the surface of the bottom portion of the panel 43.
  • the forming steel strip will be withdrawn through the gap between these two portions.
  • a typical gap may be in the region of 12 mm.
  • the wall 68 is C-shaped in section, and cooperates with a vertical panel 69 to define a water chamber 70, fed through pipes 72 and 74.
  • the wall 68 may also have a boron nitride or equivalent coating 76 which is intended to reduce friction with the strip.
  • the provision of the chamber 24 is of advantage in that 1) it allows the use of conventional feed means such as nozzles, and 2) it promotes stabilization of the melt temperature.
  • first solidification zone extending from the level of the upper wall 60 (at the top of the panel 43) down to the level of the bottom of the refractory block 36
  • second solidification zone extending below the first solidification zone as far as the bottom of the further cooling wall 68.
  • the rightward face of the ultimate strip is formed against the vertical face 28 of the panel 43 in the first solidification zone
  • the leftward face of the ultimate strip is formed against the further cooling wall 68 in the secondary solidification zone.
  • Figure 7 is a schematic vertical sectional view of another embodiment of this invention, somewhat distorted in terms of the strip thickness in order that the process of strip solidification can be better understood.
  • a chamber 224 is shown to be defined in part between a sloping insulating wall 232 and a vertical cooling wall 228, the latter being of high-­conductivity copper coated with boron nitride.
  • the cooling wall 228, against which water jets 252 are directed, has a cooling effect only up to its top flange 260.
  • the numeral 262 identifies insulating material above the cooling wall 228, thus ensuring that slag and impurities at the surface of the melt will not be drawn into the forming strip.
  • the first solidification zone is encompassed by the bracket 245, which in this embodiment extends only to the bottom of the cooling wall 228.
  • the secondary solidification zone extends as far as the bottom of a cooling unit 268, the construction of which would be the same as that shown at 68, 69 and 70 in Figure 2.
  • the secondary solidification zone is encompassed by the bracket 247.
  • the thickness of the forming strip is exaggerated. As can be seen by the profile 270, the strip progressively increases in thickness in the downward direction within the first solidification zone 245, due to the cooling effect of the cooling wall 228. Once the strip has left the first solidification zone, however, the increase in thickness from the right side proceeds at a very reduced rate. Within the secondary solidification zone, the cooling effect of the unit 268 causes solidification to proceed from the left side, rapidly increasing in thickness until the entire strip is solid. Solidification is preferably completed within the secondary solidification zone 247. In a preferred embodiment, the unit 268 undergoes oscillation which may be horizontally parallel to the strip, or vertically, or a combination of these motions.
  • shrinkage cavities or voids 271 will occur along the interior plane where the two solidification fronts come together.
  • these voids are welded together (eliminated) by withdrawing the formed strip 273 using extraction rolls 275 which not only pinch and pull the strip 273 downwardly, but also reduce its thickness.
  • the pressure applied to achieve thickness reduction can be adjusted to weld up any contained voids 271.
  • back-up rolls could be used to reduce any tendency for the strip to develop a crown as a result of the thickness reduction process.
  • the rolls 275 serve several purposes: 1) they weld up the voids, as already stated, 2) they planish the surface to make it smoother, and 3) they achieve the final thickness specified by the customer without having to change the gap from the first to the second solidification zone.
  • pressure rolls 279 which are resiliently mounted so as to exert a leftward force against the strip in the secondary solidification zone. This force keeps the strip pressed against the cooling unit 268, thus preventing a breakout of molten metal in the secondary solidification zone. It is contemplated to provide a stop for the rolls 279, which fixes the minimum distance between the cooling unit 268 and the rolls 279. In the embodiment of Figure 2 the rolls 279 are not present, because the panel 43 extends through to the bottom of the secondary solidification zone 247. However, the embodiment of Figure 2 will require a greater degree of monitoring and control, since the gap between the panel 43 and the wall 68 is fixed.
  • heating elements 281 are also illustrated in Figure 7 because a plurality of heating elements 281, the purpose of which is to add heat to the melt to ensure that it remains above the liquidus temperature.
  • the lowermost heating element 281a is of particular importance because it adds heat close to the critical neck area where alumina could be deposited against the wall 232.
  • the variant shown in Figures 4-6 includes a lower sealed water chamber 80 fed by an inlet tube 82, an upper sealed water chamber 84 delivering water to an outlet tube 86, and a plurality of laterally spaced vertical grooves 88 linking the chambers 80 and 84, the configuration of the grooves being best seen in Figure 6.
  • Figure 6 is a horizontal section which cuts through the panel 68 toward the bottom of the Figure 5 structure, and it will be seen that the panel 68 is integral with two end structures 90 which are movable in such a way that the lateral spacing between the panel 68 and the panel 43 can be adjusted. This adjustability allows control of the initial thickness of the strip.
  • Figures 4-6 show the panel 43 as one layer of a three-part composite plate which includes layers 43a and 43b. While such a construction could be employed, it is considered that a single layer (as in Figures 2 and 7) is preferable.
  • this invention contemplates the use of oscillation or vibration in order to reduce sticking of the strip to the cooling walls. More particularly, it is contemplated to provide a particular pattern of oscillation in a "walking" arrangement, wherein the panel 43 moves in a closed loop.
  • the closed loop involves, in sequence, inward (leftward) movement to achieve contact with the forming strip, then downward movement to urge the strip downwardly, then outward (rightward) movement to break or reduce contact with the strip, then upward movement.
  • Such a repeating cycle will encourage the solidifying strip to move downwardly, since upward movement of the panel 43 occurs after it has withdrawn away from the strip.
  • the cyclic motion of the panel 43 just described will leave oscillation marks on the product.
  • Figure 7 further illustrates in broken outline a housing 282 encompassing the rolls 275 and the secondary zone 247.
  • the housing 282 provides a reducing atmosphere to diminish scale formation and to prevent reoxidation of the metal strip.
  • boron nitride as a coating on panel 43 does not imply a limitation in terms of the scope of the invention.
  • the important thing about the panel 43 is that it be capable of transferring heat away from the chamber 24, and that it present a relatively "slippery" surface to the hot melt.
  • a new material called SIALON may prove to be equivalent or superior to boron nitride for the coating.
  • the coating material should have extreme temperature resistance under reducing and even oxidizing conditions (i.e. around 1600° C). Further, it should have excellent geometric thermal stability, i.e. a low or zero coefficient of thermal expansion.
  • thermo-conductivity of the material should be at least as high as that of steel, and ideally it should have a low heat capacity. While boron nitride is not ideal in terms of a low heat capacity, its low density tends to compensate to some degree. Finally, the material should have a "non-wetting" aspect and low friction, since this tends to overcome or reduce any “coupling” friction with respect to the strip. It is considered that a modest amount of "sliding friction" will be beneficial for a proper application of the walking oscillation described earlier.
  • the apparatus of the present invention could have other orientations than that illustrated.
  • the surface 28 in Figure 2 could be angulated with respect to the vertical.
  • Temperature control regulates the rate of cooling (solidification) of molten metal on the cooling wall and also regulates or maintains the molten metal temperature in the mold for casting. This is critical to attaining a high quality product.
  • Controlled cooling in both the longitudinal and transverse directions at the cooling wall is considered important for the attainment of flat strip with good surface quality.
  • the water spray system is not mechanically connected to the panel 43, which leaves the panel free owing to the decreased mass, to oscillate more readily at any desired impressed frequency.
  • Control of the spray nozzles may be accomplished by thermocouples embedded in the panel 43 at various locations or zones.
  • the thermocouples could provide data for computer analysis and control of the cooling on a zone-by-zone basis.
  • the fins 50 integral with the panel 43 assist in defining the cooling zones, increase cooling capacity, and prevent distortion of the panel 43.
  • the governing design criterion for the vertical oscillator component for a thin strip caster is that the maximum mold velocity must exceed the strip velocity to produce a stripping effect between the strip and the cooling wall.
  • the horizontal oscillation component for a thin strip casting machine will be coupled to the vertical motion to simulate a "walking beam" effect.
  • the mold will remain in contact with the steel strip during the down stroke of the vertical motion. At the end of the down stroke the mold will move horizontally away from the strip. Contact between the mold and the strip will not occur again until the mold is at the top of its vertical stroke.
  • the oscillator frequency in the horizontal plane must be the same as the oscillator frequency in the vertical plane.
  • the stroke length will be selected based on the desired stand-off distance between the mold and the steel strip.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Continuous Casting (AREA)
EP89304760A 1988-05-10 1989-05-10 Procédé et dispositif de coulée de bande de métal Withdrawn EP0342020A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB888811028A GB8811028D0 (en) 1988-05-10 1988-05-10 One-face strip casting mould
GB8811028 1988-05-10

Publications (2)

Publication Number Publication Date
EP0342020A2 true EP0342020A2 (fr) 1989-11-15
EP0342020A3 EP0342020A3 (fr) 1990-02-07

Family

ID=10636647

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89304760A Withdrawn EP0342020A3 (fr) 1988-05-10 1989-05-10 Procédé et dispositif de coulée de bande de métal

Country Status (9)

Country Link
EP (1) EP0342020A3 (fr)
JP (1) JPH0270355A (fr)
KR (1) KR890017019A (fr)
CN (1) CN1040337A (fr)
AU (1) AU3460589A (fr)
BR (1) BR8902184A (fr)
DD (1) DD283783A5 (fr)
GB (1) GB8811028D0 (fr)
HU (1) HUT49823A (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109036073B (zh) * 2018-08-30 2020-12-29 中南大学 一种模拟薄带连铸结晶辊表面氧化膜生成的装置及其方法

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1095486A (fr) * 1900-01-01
GB967699A (en) * 1963-01-14 1964-08-26 James Nelson Wognum Continuous casting
US3450188A (en) * 1966-08-23 1969-06-17 Enn Vallak Continuous casting method and arrangement
DE1783170A1 (de) * 1964-11-12 1974-04-04 Southwire Co Verfahren zum kontinuierlichen herstellen eines metallischen strangs und vorrichtung zur durchfuehrung des verfahrens
JPS5524710A (en) * 1978-08-09 1980-02-22 Hitachi Ltd Casting method
JPS60137551A (ja) * 1983-12-26 1985-07-22 Nippon Mining Co Ltd 水平連続鋳造法及び同用鋳型
WO1988000868A1 (fr) * 1986-08-08 1988-02-11 Kurzinski Cass R Appareil et procede permettant de couler en continu des brames d'acier

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1095486A (fr) * 1900-01-01
GB967699A (en) * 1963-01-14 1964-08-26 James Nelson Wognum Continuous casting
DE1783170A1 (de) * 1964-11-12 1974-04-04 Southwire Co Verfahren zum kontinuierlichen herstellen eines metallischen strangs und vorrichtung zur durchfuehrung des verfahrens
US3450188A (en) * 1966-08-23 1969-06-17 Enn Vallak Continuous casting method and arrangement
JPS5524710A (en) * 1978-08-09 1980-02-22 Hitachi Ltd Casting method
JPS60137551A (ja) * 1983-12-26 1985-07-22 Nippon Mining Co Ltd 水平連続鋳造法及び同用鋳型
WO1988000868A1 (fr) * 1986-08-08 1988-02-11 Kurzinski Cass R Appareil et procede permettant de couler en continu des brames d'acier

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN, vol. 4, no. 57 (M-9)[539], 26th April 1980 page 92 M 9; & JP-A-55 024 710 (HITACHI SEISAKUSHO K.K.) 22-02-1980 *
PATENT ABSTRACTS OF JAPAN, vol. 9, no. 300 (M-433)[2023], 27th November 1985; & JP-A-60 137 551 (NIPPON KOGYO K.K.) 22-07-1985 *

Also Published As

Publication number Publication date
CN1040337A (zh) 1990-03-14
EP0342020A3 (fr) 1990-02-07
KR890017019A (ko) 1989-12-14
HUT49823A (en) 1989-11-28
DD283783A5 (de) 1990-10-24
GB8811028D0 (en) 1988-06-15
JPH0270355A (ja) 1990-03-09
BR8902184A (pt) 1990-01-02
AU3460589A (en) 1989-11-16

Similar Documents

Publication Publication Date Title
US5762127A (en) Method to control the deformations of the sidewalls of a crystalliser and continuous-casting crystalliser
WO2000041828A1 (fr) Cristalliseur pour coulee continue
US4911226A (en) Method and apparatus for continuously casting strip steel
EP0342020A2 (fr) Procédé et dispositif de coulée de bande de métal
FI78250C (fi) Foerfarande och anordning foer direktgjutning av smaelt metall.
US3339623A (en) Thermal bending of continuous castings
JP3089608B2 (ja) ビームブランクの連続鋳造方法
EP0387006A2 (fr) Dispositif à deux parois convergentes pour machine de coulée de bandes
EP0743115B1 (fr) Méthode et appareil pour la coulée continue de l'acier
FI78249B (fi) Foerfarande och anordning foer direktgjutning av smaelt metall till ett fortloepande kristallint metallband.
CN1011867B (zh) 金属尤其是钢的带材连铸工艺方法及其设备
US5299627A (en) Continuous casting method
JPS609553A (ja) 絞り込み式連続鋳造機
JPH08132184A (ja) 丸ビレット鋳片の連続鋳造用鋳型及びその鋳型を用いた連続鋳造方法
JP3216476B2 (ja) 連続鋳造方法
JPH01170551A (ja) 鋼の連続鋳造用鋳型
JP3130152B2 (ja) 双ベルト式連続鋳造機及びその注湯方法
JPS6087956A (ja) 金属の連続鋳造法
JPS6130260A (ja) 双ロ−ル鋳造用溶融金属注入装置
JPS5835050A (ja) 溶湯の加熱機能を有する連続鋳造用タンデイツシユ
JP2845706B2 (ja) 連続鋳造設備のモールド装置
JPS61150751A (ja) 金属の水平連続鋳造のための加熱鋳型及び方法
JPH07227653A (ja) 連続鋳造における収縮孔低減方法および装置
JPS63165053A (ja) 中心偏析の少ない連続鋳造方法
JPH01127147A (ja) 溶融金属の鋳造方法

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19890531

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): AT BE CH DE ES FR GB GR IT LI LU NL SE

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): AT BE CH DE ES FR GB GR IT LI LU NL SE

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN

18W Application withdrawn

Withdrawal date: 19910225

R18W Application withdrawn (corrected)

Effective date: 19910225