US3741277A - Process for continuously operating a continuous casting plant - Google Patents

Process for continuously operating a continuous casting plant Download PDF

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Publication number
US3741277A
US3741277A US00207481A US3741277DA US3741277A US 3741277 A US3741277 A US 3741277A US 00207481 A US00207481 A US 00207481A US 3741277D A US3741277D A US 3741277DA US 3741277 A US3741277 A US 3741277A
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United States
Prior art keywords
casting
tundish
mould
new
level
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US00207481A
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English (en)
Inventor
E Bachner
W Fortner
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Voestalpine AG
Voest AG
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Voestalpine AG
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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

Definitions

  • ABSTRACT The invention relates to a process for continuous continuous casting of liquid metals wherein a series of melts are cast from ladies into an exchangeable tundish wherefrom the metal runs into a water-cooled mould via a casting tube extending into said mould.
  • the tundish exchange is carried out by removing the worn tundish from casting position, moving a new, empty tundish above the mould in a manner that its casting tube extends in to the mould, driving a ladle containing hot liquid metal above the tundish and filling the new tundish when it is in casting position. While the tundish is being exchanged the casting level in the mould is lowered to a position below the outflow opening of the casting tube and is kept there until metal runsfrom the new tundish into the mould. This is preferably achieved by reducing the drawing out speed of the cast bar. By using an empty tundish it becomes possible to exchange the tundishes immediately. Furthermore, the yields and operational safety are greatly increased by the invention.
  • the invention relates to a process for continuous casting of hot liquid metals, in particular steel, wherein a number of melts are successively cast from ladies into a tundish whence the metal is permitted to run into a water-cooled mould via a casting tube extending into it, whereupon the cast bar still having a liquid core is drawn out and further cooled in a secondary cooling zone, the tundish being exchangeable.
  • This plant comprises two bearing arms each of which is rotatable around a vertical axis and carries a casting ladle, and at least one exchangeable tundish, both bearing arms independently of each other being rotatable from an initial position, the ladle feed position, into opposite directions to two operating positions; the tundish or the tundishes are likewise rotatable, namely from a resting position to the casting position.
  • This arrangement is to enable continuous casting without interruption, even if disturbances should occur at one tundish, as e.g., at a stopper or outflow; in this case a tundish which is filled with hot liquid metal and ready for casting has to be brought without delay into casting position.
  • the ladle has to be removed from its operation position, then the tundish to be exchanged has to be lifted to a height at which the bottom margin of the casting tube lies above the upper margin of the mould, then the tundish to be exchanged has to be removed, the new tundish filled with liquid metal has to be lifted, moved into position above the mould'and then it has to be lowered into operation position, whereupon the metal supply into the mould may be resumed.
  • the waiting time amounts to at least 1.5 min. until the tundish is filled and casting thus may be continued.
  • the invention resides in that in an exchange of the tundish the tundish is moved away from the casting position and a new, empty tundish is positioned above the mould in a manner that its casting tube extends into the mould, whereupon a ladle containing hot liquid metal is moved above the tundish and the tundish is filled, wherein, when the new tundish is being brought into position, the casting level in the mould is brought to a position below the outflow opening of the casting tube and is kept so long in this position until the metal runs from the new tundish into the mould, whereupon the casting level in the mould is lifted again.
  • the outflow opening of the casting tube has to be kept free from liquid steel in the mould, until steel is delivered from the ladle into the tundish; this, however, is only possible when the tundish is sufflciently lowered, i.e., so far that the casting ladle may be brought into its operation position above the tundish. If the casting level were not lowered during the exchange, liquid steel would enter through the outflow opening into the casting tube and freeze there; then it would not be possible to continue casting.
  • the drawing out speed of the cast bar is reduced and after the exchange of the. tundish increased again, a uniform drawing out speed of 0.1 to 0.2 'm./min. being preferably maintained while the tundish is being exchanged independently from the original drawing out speed and from the other casting conditions.
  • FIG. 1 is a lateral view of the upper part of a continuous casting plant, partly in section; it shows how the metal is supplied to the mould.
  • FIGS. 2 and 3 show the changes of the casting level in the mould during and after the exchange of a tundish.
  • numeral 1 denotes a stopper ladle, which is horizontally displaceable in direction of the double arrow; the ladle may be moved either on a bearing arm which is rotatable around a vertical rotation axis or on a carriage displaceable on a straight or circular path.
  • Numeral 2 denotes a liftable, lowerable and horizontally displaceable tundish below the ladle 1, which is provided with a casting tube 3 having several outflow openings 4 spaced around the circumference of its lower end.
  • the casting tube may be closed by a stopper (not shown) in customary manner, by means of which the metal supply into the mould can be controlled.
  • Numeral 5 refers to a water-cooled continuous casting mould which oscillates in vertical direction, and from which a cast bar 6 with a solidified bar shell 7 and a liquid core 8 is drawn out;
  • FIG. 1 does not show the device joined to the mould for guiding and drawing out the bar in which the bar is cooled until it is completely solidified, nor does it show the separating means by which it is severed into pieces.
  • Numerals 9,10,l 1,12,13 denote horizontal planes; plane 9 is laid through the casting level of the liquid metal in the mould 5 in a position maintained during normal operation, i.e., when the tundish is not being exchanged, plane 10 is laid through the upper margin of the mould, plane 1 l is laid through the bottom margin of the casting tube 3 when the tundish is in normal operation position, plane 12 is laid through the bottom margin of the stopper ladle 1, and plane 13 is laid through the upper margin of the tundish 2 when it is in normal operation position.
  • the level difference between the planes 10 and 9 amounts to 50 mm and the level difference between planes 9 and 11 to from 100 mm to 150 mm, i.e., the outflow openings 4 lie below the casting level 9.
  • the casting tube 3 is closed at its lower end and its outflow openings 4 are downwardly slanting by an angle of 25 to the horizontal line.
  • the outflow openings 4 may also extend horizontally, or slant in upward direction.
  • Numeral 14 denotes a tundish which is in the reserve position; it has a casting tube 3' and outflow openings 4'; the stand-by tundish is, like the tundish 2, liftable, lowerable and horizontally displaceable in direction of the double arrows.
  • the tundishes 2, 14 are movable by means of devices, not shown, e.g., rotatable arms or carriages.
  • the empty tundish is in pre-heated condition and ready for being exchanged against the tundish 2.
  • the tundish 14 must be arranged above the mould sufficiently high so that the horizontal plane 15 laid through the lower margin of the casting tube 3' lies above the plane of the upper margin of the mould.
  • the maximum lifting height of the tundish corresponds to the level difference between the planes l5 and 11 and in the present case amounts to 400 mm.
  • the horizontal plane 16 laid through the upper margin of the tundish 14 lies above the plane 12, i.e., the casting ladle 1 cannot be moved above the tundish 14 in reserve position.
  • the stopper ladle 1 When the tundishes are to be exchanged, at first the stopper ladle 1 is moved to the left from its operating position into a waiting position and then the tundish 2 is removed from its operating position; in doing so, it is not absolutely necessary, to lift the tundish 2 prior to the horizontal displacement perhaps to the levels or 16, respectively, but it is possible to break off the casting tube 3 which at this stage is already greatly worn, during the horizontal displacement and to remove later the broken piece from the mould hollow space.
  • the casting level 9 is lowered by 100 to 150 mm to the position 17(FlG. 2).
  • the drawing out speed of the cast bar which originally amounted to about 1.0 m./min. is reduced to 0.1 m./min.; the casting level thus sinks slowly, while the tundish 14 is brought into position above the mould 5 and then lowered.
  • the tundish 14 is lowered at first only so far that the casting ladle 1 or a second casting ladle, not shown, may be moved above the tundish l4 and filling of the tundish may be started (FIG. 2).
  • the tundish is lowered into the final operation position, in which the bottom margin of the casting tube 3 reaches plane 11 (FIG. 3). In this position, the casting tube 3 penetrates a layer of casting powder 19 on the casting level. The casting powder prevents the steel from solidifying while the metal supply to the mould is interrupted. As soon as the original position 9 of the casting level is reached again, the continuous casting drawing out speed is increased again to about 1.0 m./min. at which point the exchange of the tundish is completed. It is also possible to lower the casting level during the exchange of the tundish without altering the drawing out speed and then interrupt drawing out of the bar until the original casting level is reached again.
  • an exchange of the tundish is carried out when a predetermined length of a bar section is reached; in other words: when the bar is severed, the separation cut is carried out in the area of connection where the metal coming from the old and new tundishes meet, which area may be discerned from the outside of the bar by a so-called set-off, which ordinarily occurs at any interruption of the metal supply to themould.
  • an empty tundish may be utilized in the tundish exchange apart from avoiding the disadvantages described in the introduction affords the additional advantage that the tundish may immediately be exchanged also if casting disturbances should occur suddenly, e.g., in case of a casting tube failure; in such a case, if necessary, also a tundish may be used that is not completely preheated because the metal gets from the casting ladle into the mould within the shortest period and thus cannot freeze in the tundish.
  • the preparation time that is the time used for filling and manipulation
  • a process for continuously operating a continuous casting plant for hot liquid metals including steel comprising casting a plurality of melts successively from ladles into exchangeable tundishes placed in a casting position in which the metal is permitted to run into a water-cooled continuous mould via respective tundish casting tubes extending into said mould and having at least one outflow opening submersed below casting level to form a cast bar,

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Continuous Casting (AREA)
US00207481A 1970-12-14 1971-12-13 Process for continuously operating a continuous casting plant Expired - Lifetime US3741277A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
AT1120570A AT314120B (de) 1970-12-14 1970-12-14 Verfahren zum vollkontinuierlichen Gießen schmelzflüssiger Metalle, insbesondere Stahl

Publications (1)

Publication Number Publication Date
US3741277A true US3741277A (en) 1973-06-26

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ID=3627418

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US00207481A Expired - Lifetime US3741277A (en) 1970-12-14 1971-12-13 Process for continuously operating a continuous casting plant

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US (1) US3741277A (enExample)
JP (1) JPS5118890B1 (enExample)
AT (1) AT314120B (enExample)
BE (1) BE776634A (enExample)
BR (1) BR7108280D0 (enExample)
CA (1) CA957129A (enExample)
CH (1) CH528940A (enExample)
ES (1) ES397908A1 (enExample)
FR (1) FR2117925B1 (enExample)
GB (1) GB1364124A (enExample)
IT (1) IT943893B (enExample)
SE (1) SE373054B (enExample)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3865175A (en) * 1972-02-03 1975-02-11 Voest Ag Process for separating non-metallic inclusions from hot liquid metal
US4903752A (en) * 1988-08-10 1990-02-27 Rokop Corporation Hot metal supply for continuous casing and the like
EP0861697A1 (en) * 1997-02-20 1998-09-02 Kvaerner Metals Continuous Casting Limited Continuous casting method and apparatus therefor

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3865175A (en) * 1972-02-03 1975-02-11 Voest Ag Process for separating non-metallic inclusions from hot liquid metal
US4903752A (en) * 1988-08-10 1990-02-27 Rokop Corporation Hot metal supply for continuous casing and the like
EP0861697A1 (en) * 1997-02-20 1998-09-02 Kvaerner Metals Continuous Casting Limited Continuous casting method and apparatus therefor

Also Published As

Publication number Publication date
CH528940A (de) 1972-10-15
BE776634A (fr) 1972-04-04
BR7108280D0 (pt) 1973-05-29
SE373054B (enExample) 1975-01-27
CA957129A (en) 1974-11-05
ES397908A1 (es) 1974-06-16
JPS5118890B1 (enExample) 1976-06-14
IT943893B (it) 1973-04-10
GB1364124A (en) 1974-08-21
AT314120B (de) 1974-03-25
FR2117925A1 (enExample) 1972-07-28
FR2117925B1 (enExample) 1974-12-20

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