EP1183118B1 - Automation of a high-speed continuous casting plant - Google Patents

Abstract

A system provided in a high-speed continuous casting plant for casting a metallic strand for automatically operating the high-speed continuous casting plant. In the system, the stopping or slide movement, the modification of the steel level, the heat currents through the mold walls, the temperature of the liquid metal and the drawing-off speed are measured over the casting time, supplied to a computer and compared with predetermined limit values for an automatic operating mode.

Description

The invention relates to a method according to the preamble of claim 1 and a system according to the preamble of claim 7. Especially when operating of high-speed systems for slabs and especially in In connection with rolling mill systems, it is important to include the continuous caster at a high and controlled speed.

This need for casting reliability, especially at high casting speeds up to 10 m / min makes it necessary to control numerous Process data that are complexly interlinked with one another with the help of automation make.

This automation must be simple in its external operating language Functional language that is easy to understand by the operating personnel become.

• eine kontrollierte Stahltemperatur im Verteiler,
• ein guter oxidischer Reinheitsgrad des Stahles,
• ein ruhiger Gießspiegel sowie
• ein konstanter und gleicher Wärmestrom der Breitseiten

gegeben sind.Furthermore, the degree of automation, which in its operating language only knows the choice of the casting speed and the control of the narrow side heat flows on the operator (NO) or drive (ND) side, should allow the possibility of an autopilot to drive if certain preconditions how

• a controlled steel temperature in the distributor,
• a good degree of oxide purity of the steel,
• a quiet casting mirror as well
• a constant and equal heat flow on the broad sides

given are.

The measurement of the heat flows of all four Cu plates of a slab mold (DE 4117073) is known as prior art, but no prior art is disclosed in this patent depending on the casting speed. So z. B. an increase in speed has a slight influence on the mold load, expressed as MW / m ² and a strong influence on the strand shell load, expressed as MWh / m ² .

Figure 1 shows this relationship and shows that at high casting speeds, when using casting powder and a certain casting speed of z. B.> 4.5 m / min the mold load remains almost constant and the strand shell load decreases sharply. The reason for this is a constant slag lubrication film at high casting speeds and therefore constant heat transfer, but a shorter dwell time of the strand shell in the mold, which is proportional to the increase in casting speed. The picture makes it clear that with increasing casting speed the mold load no longer rises and the strand shell load decreases, which reduces the risk of cracking but also the strand shell z. B. becomes thinner and hotter at the end of the mold.

• Gießschlackenfilm,
• Strangschalentemperatur, z. B. am Kokillenaustritt, Strangschalendicke und Schrumpf,
• Kokillen- und Strangschalenbelastung bzw. Schrumpf,
• max. Kokillenhauttemperatur im Gießspiegel und damit der Kokillenstandzeit in Relation zur Rekristallisationstemperatur, die zur Erweichung des kaltgewalzten Kupfers führt.

The relationships between are shown in FIG

• casting slag,
• Strand shell temperature, e.g. B. at the mold exit, strand shell thickness and shrinkage,
• Mold and strand shell loading or shrinkage,
• Max. Mold skin temperature in the mold level and thus the mold life in relation to the recrystallization temperature, which leads to the softening of the cold-rolled copper.

From US-A-3 478 808 is a method for controlling parameters in one Continuous casting plant for casting steel known. Target values of parameters, which were taken from previous casting processes, saved, actual values parameters, a comparison between actual and target values carried out and a regulation of the influencing variables. As a parameter are among others the flow rate, the rate of heat removal within the mold and the pull-off speed.

Proceeding from this, the object of the invention is a method and a System for carrying out the method for the controlled operation of a continuous caster for casting slabs, especially thin slabs, with very high To further develop casting speeds.

This object is achieved with a method having the features of claims 1 and a system with the features of claim 7 solved. Advantageous further developments are disclosed in the subclaims.

• Halbautomatik, d. h. der Steuerung von Schmalseitenkonizitäten und Gießgeschwindigkeit, auch eine
• Vollautomatik im Sinne einer Auto-Pilot-Fahrweise

zuläßt unter der Berücksichtigung und in Funktion der Stahltemperatur im Verteiler und unter der Voraussetzung eines kontrollierten

• Reinheitsgrades,
• Gießspiegels und
• Breitseitenwärmestroms.

Automation of the continuous casting process is made possible on the basis of an 'online' data acquisition, which is both in addition to a

• Semi-automatic, ie the control of narrow side conicity and casting speed, also one
• Fully automatic in the sense of an auto-pilot driving style

permits taking into account and in function of the steel temperature in the distributor and under the condition of a controlled

• Purity,
• Pouring mirror and
• Broadside heat flow.

Figur 1:

Die Kokillen- und Strangschalenbelastung in Abhängigkeit von der Gießgeschwindigkeit;

Figur 2:

Die Zusammenhänge zwischen der Gießgeschwindigkeit und

• Schlackenfilmdicken,
• Strangschalentemperatur, Schrumpf sowie Strangschalendicke am Ausgang der Kokille,
• Kokillen- und Strangschalenbelastung sowie Schrumpf,
• Temperaturbelastung der Kupferplatte im Gießspiegel sowie die Standzeit der Cu-Platten relativiert an der Rekristallisationstemperatur der kaltgewalzten Kupferplatte.

The figures serve as examples to illustrate the invention and are described below. Show it:

Figure 1:

The mold and strand shell loading depending on the casting speed;

Figure 2:

The relationship between the casting speed and

• Slag film thicknesses,
• Strand shell temperature, shrinkage and strand shell thickness at the exit of the mold,
• Mold and strand shell loading as well as shrinkage,
• The thermal load on the copper plate in the mold level and the service life of the copper plates are relativized at the recrystallization temperature of the cold-rolled copper plate.

Figur 3:

stellt

a) eine Brammenkokille (1) mit (1.1) und ohne Eingießtrichter und in ihrer Konizität und verstellbaren Schmalseiten (1.2) sowie Tauchausguß (1.4) und Gießpulver,

b) die Kokillenbelastung, ausgedrückt als MW/m² für Breitseiten (WL) und (WF) sowie für die Schmalseiten (ND) und (NO) über die Gießzeit und

c) das Verhältnis der Wärmeströme von Breitseiten zu Schmalseiten, ausgedrückt als NO/WL, NO/WF und ND/WL, NO/WF, die den Verlauf der Wärmeströme einfacher beschreiben und ihre Korrektur über die Konizitätsanstellung während des Gießerns leichter gestalten,

dar.

Figur 4:

stellt Gießsituationen A, B, C mit Hilfe

a) der Wärmeströme, ausgedrückt als MW/m², bzw.

b) des Verhältnisses der Wärmeströme ND/WF, ND/WL und NO/WF, NO/WL, die eine Korrektur durch Verstellung der Schmalseiten in ihrer Konizität von der Position 0 zu der Position 1 erfahren,

dar.

Figur 5:

stellt den Temperaturverlauf von Schmelzen im Verteiler über eine Gießzeit von einer Stunde dar.

Figur 6:

stellt das Gießfenster, gebildet zwischen der Stahltemperatur im Verteiler und der Gießgeschwindigkeit, mit den beispielhaften Temperaturverläufen unterschiedlicher Schmelzen dar.

Figur 7:

stellt die Datenerfassung und den Regelkreis im Bereich der Stranggießmaschine mit den Eingaben an Grenzwerten für die Steuerung und Regelung der Schmalseitenkonizitäten und der max. Gießgeschwindigkeit in Funktion von der Stahltemperatur im Verteiler dar.

FIGS. 1 and 2 have already been described in detail as prior art and serve for a better understanding of the following description, which is not to be taken for granted for a normal technician and thus has an inventive level.

Figure 3:

provides

a) a slab mold (1) with (1.1) and without pouring funnel and in its conicity and adjustable narrow sides (1.2) as well as immersion spout (1.4) and casting powder,

b) the mold load, expressed as MW / m ² for broad sides (WL) and (WF) as well as for the narrow sides (ND) and (NO) over the casting time and

c) the ratio of the heat flows from broadsides to narrow sides, expressed as NO / WL, NO / WF and ND / WL, NO / WF, which describe the course of the heat flows more easily and make their correction via the taper adjustment easier during casting,

represents.

Figure 4:

provides casting situations A, B, C with the help

a) the heat flows, expressed as MW / m ² , or

b) the ratio of the heat flows ND / WF, ND / WL and NO / WF, NO / WL, which are corrected by adjusting the narrow sides in their taper from position 0 to position 1,

represents.

Figure 5:

shows the temperature curve of melts in the distributor over a casting time of one hour.

Figure 6 :

shows the casting window, formed between the steel temperature in the distributor and the casting speed, with the exemplary temperature profiles of different melts.

Figure 7:

provides the data acquisition and the control loop in the area of the continuous casting machine with the inputs to limit values for the control and regulation of the narrow side conicity and the max. Casting speed as a function of the steel temperature in the distributor.

Figure 3 consists of the sub-figures a), b) and c). FIG. 3 a) shows schematically a slab or bloom block (1), each consisting of two individual narrow sides (1.2), which on the operating side (1.2.1) (NO) and drive side (1.2.2) (ND) with adjusting cylinders (1.2.3) are provided, and two broad sides (1.3), the back (1.3.1) (WF) and the loose side (1.3.2) (WL).

The mold (1) can also advantageously be equipped with a pouring funnel (1.1) be provided. The liquid steel (1.4) is covered by the immersion spout (1.5) the bath level (1.7.2) into the mold when using casting powder (1.6) with formation of pouring slag (1.6.1) and a pouring slag film between the mold (1) and strand shell (1.7.1), for lubrication and for heat flow control serves, directed.

Figure 3 b) and c) show the specific heat flow in MW / m ^{2 of} the broad side WF, WL (1.3.2) and the narrow sides NO (1.2.1), NO (1.2.2) in normal. inconspicuous casting process, the casting time from start to time tx, at which the steel is in temperature equilibrium with the distributor. The narrow side streams have to show a ratio to the broad sides of <1 via the conicity of the narrow sides, which must be kept constant over the casting time.

Different slag films formed over the strand circumference, especially between broad and narrow sides, different casting speeds different steel temperatures, non-uniform flow conditions in the left and right half of the mold, a deflection of the slab the strand center axis in the casting direction can lead to deviations in the specific Heat dissipation.

These deviations are shown in FIG. 4 in three typical cases A, B and C (FIG. 4)) on the basis of the specific heat flows, expressed as MW / m ² in FIG. 4 b) , and as the heat flow ratio narrow side / broad sides (N / W) in FIG 4 c) .

In case A, the heat flow gives way to the narrow side on the drive side (LP) (1.2.2) of that of the narrow side on the thick side (NO) (1.2.1) by a heat flow too low. By increasing the conicity the ND narrow side from position 0 to position 1, the heat flow is that of Adjusted (NO) narrow side.

In case B, the heat flows are on both narrow sides compared to the Broad sides too high. By withdrawing the conicity job of both Narrow sides from position 0 to position 1, the heat flows into the correct relationship to the broadsides set.

In case C, the heat flows on the narrow sides are too low and can occur a simultaneous increase in the narrow side taper from position 0 to Position 1 are brought to their correct value relative to the broadsides.

• Verweilzeit des Stahles im Verteiler, d. h. von der Gießleistung und der
• Isolation des Verteilers.

Figure 5 shows the temperature profile of numerous melts over a period of approximately 1 hour in the distributor. It can be seen that, for example, in these pans with a melt content of approx. 180 t, the steel temperature drops by approx. 5 ° C./hour. This drop in the steel temperature in the distributor can be kept relatively low and depends essentially on the

• Steel dwell time in the distributor, ie the casting performance and the
• Isolation of the distributor.

• Pfannenlaufzeiten,
• Pfannenalter und
• Pfannenmauerung,

die häufig durch eine unkontrollierte Verfahrweise zu Abweichungen von der Soll-Temperatur führen.The absolute temperature at which the steel enters the distributor is specified by the continuous casting operation, is set by the steelworks and depends on, for example

• Pan maturities,
• Pan age and
• Pfannenmauerung,

which often lead to deviations from the target temperature due to an uncontrolled procedure.

Figure 6 shows the pouring window, formed by the steel temperature in the distributor and the maximum possible casting speed.

• größerem Verteilervolumen,
• verbesserter Verteilerisolation,
• Einsatz einer elektromagnetischen Bremse in der Kokille.

The pouring window (4) is formed by an upper (3.0) and lower (3.1) temperature limit. Furthermore, in addition to the steel temperature in the mold (3.3), the range of the liquidus temperature (3.4) of z. B. Low carbon steel grades are shown. The steel temperature in the mold increases with a constant steel temperature in the distributor inlet

• larger distribution volume,
• improved distributor insulation,
• Use of an electromagnetic brake in the mold.

The diagram in FIG. 6 shows three melts with different distributor temperatures and therefore different maximum possible casting speeds, but for example the same temperature loss of 5 ° C / hour represents.

These three cases in the pouring window (4) are shown in detail as follows.

In case (4.1) the steel temperature at the start of casting is 1.570 ° C and allowed a maximum casting speed (1.8) of 4.0 m / min, and after 1 hour Casting time at the end of the ladle casting time allows the steel temperature of 1,565 ° C a maximum casting speed of 4.5 m / min.

In case (4.2), the steel temperature in the distributor at the start of casting is Melt 1,560 ° C and at the end of casting 1,555 ° C, which is a maximum casting speed of 5.0 m / min and at the end of casting 5.85 m / min allowed.

In case (4.3) the temperature is 1,550 ° C and allows a casting speed of 7.2 m / min and one at the end of casting with a temperature of 1,545 ° C Casting speed of> 8 m / min. The speed of max. 8 m / min can be started when a temperature of approx. 1,548 ° C is reached.

Figure 7 shows the structure of a semi-automatic or fully automatic / auto-pilot for casting a high-speed system.

The system consists of the steel pan (5), a distributor (6) with a Plug or slide closure (6.1) and a discontinuous or continuous Temperature measurement in the distributor, a continuous caster with oscillating Mold (1) and adjustable narrow sides (12) as well as pull-out rollers (6.3), which are driven by a motor (6.3.1) and the line with controlled Deliver the casting speed (1.8).

• Temperaturmessung des Stahles im Verteiler (6.2) in °C,
• Stopfenbewegung oder Schieberbewegung (6.1.1) in dy/dt,
• Wärmestrommessung der Breitseiten (7) in MW/m²,
• Wärmestrommessung der Schmalseiten (8) in MW/m²,
• Stopfenbewegung,
• Gießspiegelbewegung (9) in dx/dt und
• Ist-Gießgeschwindigkeit (1.8) in m/min. Diese Daten werden in einem online-Rechner (10) mit Grenzdaten verglichen. Unter Vorbedingungen wie
• einer Stopfenbewegung von dy/dt von ± 0, d. h. ein 'clean steel', der zu keiner wesentlichen oxidischen Ablagerung im SEN sowie zu keiner Stopfen- und SEN-Erosion führt,
• einem konstanten Wärmestrom, in den Breitseiten bei konstanter Gießgeschwindigkeit mit einer Toleranz von max. 0, 1 MW/m² über die Gießzeit und zueinander,
• einer Gießspiegelbewegung von max. ± 5 mm über eine Gießzeit von 60 sec,
• einem Wärmestromverhältnis der Schmalseiten zu den Breitseiten von > 0,9 und < 0,4

kann die Bedienoberfläche (11) in Form eines 'Joysticks', der die vier Funktionen

• +/- Gießgeschwindigkeit und
• +/- Taper für die einzelnen Schmalseiten

aufweist und eine Halbautomatik darstellt, auf eine Vollautomatik oder den Status eines Auto-Piloten betriebssicher und damit durchbrucharm (< 0,5 %) umgestellt werden.The following data acquisition is necessary for the fully automatic driving style / auto pilot:

• Temperature measurement of the steel in the distributor (6.2) in ° C,
• Plug movement or slide movement (6.1.1) in dy / dt,
• Heat flow measurement of the broad sides (7) in MW / m ² ,
• Heat flow measurement of the narrow sides (8) in MW / m ² ,
• Plug movement,
• Casting level movement (9) in dx / dt and
• Actual casting speed (1.8) in m / min. This data is compared with limit data in an online computer (10). Under conditions like
• a plug movement of dy / dt of ± 0, ie a 'clean steel' which does not lead to any significant oxidic deposition in the SEN or to plug and SEN erosion,
• a constant heat flow, in the broadsides at constant casting speed with a tolerance of max. 0.1 MW / m ² over the casting time and each other,
• a mold level movement of max. ± 5 mm over a casting time of 60 sec,
• a heat flow ratio of the narrow sides to the broad sides of> 0.9 and <0.4

can the user interface (11) in the form of a 'joystick', the four functions

• +/- casting speed and
• +/- taper for the individual narrow sides

has and is a semi-automatic, can be switched to fully automatic or the status of an auto pilot reliable and therefore low breakthrough (<0.5%).

With the casting, the fully automatic system corrects the conicity settings of each individual narrow side on the basis of the heat flow conditions between narrow sides and broad sides outside of a narrow side / broad side ratio of, for example 0.8> N W > 0.5 and automatically moves in the maximum possible casting speed, which is possible due to the steel temperature in the distributor and the function set.

The invention enables reproductive operation of the continuous casting plant maximum possible productivity while avoiding breakthroughs and controlled String quality possible.

LIST OF REFERENCE NUMBERS

(1)

Slab mold with oscillation

(1.1)

funnel

(1.2)

mold narrow

(1.2.1)

Narrow side on the operator side (NO)

(1.2.2)

Narrow side on the drive side (ND)

(1.2.3)

Anstelizylinder

(1.3)

broadsides

(1.3.1)

Fixed broadside or reverse, WF

(1.3.2)

Broadside, loose side or back, WL

(1.4)

molten steel

(1.5)

Diving spout, SEN

(1.6)

casting powder

(1.6.1.1)

Pouring slag film between mold and strand shell

(1.7)

strand

(1.7.1)

strand shell

(1.7.2)

meniscus

(1.8)

Casting speed, V _c

(1.8.1)

Casting time t _x , after which the steel temperature is in equilibrium with the distributor

(3)

upper temperature limit

(3.1)

lower temperature limit

(3.3)

Steel temperature in the mold

(3.4)

Range of liquidus temperature of 'low carbon' steel grades

(3.5)

Causes of an increase in the steel temperature in the mold controlled temperature of the steel in the distributor inlet

(4)

Pouring window with three melts of different temperatures in the distributor and the same temperature loss of 5 "C / hour in Casting window steel temperature / casting speed

(4.1)

Case 1 with a melt which leads to a steel temperature in the distributor of 1,570 ° C at the start of casting and 1,565 ° C at the end of casting and a casting speed of 4.0 and max. Allows 4.5 m / min

(4.2)

Case 2 with a melt, which leads to a steel temperature in the distributor of 1,560 ° C at the start of casting and 1,560 ° C at the end of casting and a casting speed of 5.0 and max. 5.85 m / min

(4.3)

Case 3 with a melt, which leads to a steel temperature in the distributor of 1,500 ° C at the start of casting and 1,545 "C at the end of casting and allows a casting speed of 7.0 and> 8.0 m / min

(5)

steel ladle

(6)

distributor

(6.1)

Stopper or slide closure

(6.1.1)

Plug or slide movement

(6.2)

discontinuous or continuous temperature measurement of the Steel in the distributor

(6.3)

driven pull-out rollers

(6.3.1)

drive motor

(7)

Heat flow measurement in MW / m2 of the broad sides

(7.1)

Broad sides of the back, fixed side WF

(7.2)

Broad sides of the loss side, WL

(8th)

Heat flow measurement in MW / m2 of the narrow sides

(8.1)

Heat flow measurement on the operator side (NO)

(8.2)

Heat flow measurement on the drive side (LP)

(8.3)

Heat flow ratio narrow side / broad sides

(8.3.1)

Heat flow ratio operator narrow side / broad sides (NO, NO) / (WL WF)

(8.3.2)

Heat flow ratio drive narrow side / broad sides (ND, NO) / (WL WF)

(9)

Casting level movement in dx / dt

(1 0)

Online Calculator

(1 0. 1)

limits

(11)

'Joystick' user interface

(11.1)

Full Auto / Auto Pilot Status

(11.2)

Alarm for takeover in semi-automatic mode

Claims (9)

1. Method of operating a high-speed continuous casting plant for casting a metallic strip (1.7), particularly a slab, at casting speeds of at most 10 m/min with an oscillating chill mould (1), which comprises in each instance opposite chill mould narrow sides (1.2.1, 1.2.2) and chill mould wide sides (1.3.1, 1.3.2), particularly of copper plates, wherein melt flows by means of an immersion spout (1.5) or a nozzle from a distributor (6) into the chill mould (1) and the distributor (6) has a movable stopper (6.1) or a slide closure for regulation of the inflowing melt quantity, wherein the method is operated with or without casting powder (1.6), and wherein for determination of the actual casting state the following parameters are measured during the casting process (on-line):

   height of the casting level (9) of the melt in the chill mould (1) in mm/min,

   temperature (6.2) of the melt in the distributor (6) over casting time,

   actual casting speed in m/min over casting time,

   characterised in that there are additionally measured:

   stopper or slide closure movement (6.1.1) as a measure for the oxidic degree of purity over casting time,

   heat flow by way of the chill mould wide sides (WF; WL),

   heat flow by way of the chill mould narrow sides (NO; ND) in MW/m² over casting time,

   and that changes in the actual casting state are determined on the basis of the stopper or slide closure movement, the movement in casting level and the change in heat flows by way of the chill mould wide sides over a predetermined time interval, and that in the case of movement of the changes within a predetermined target interval there is changeover to an automatic mode of operation for casting, which includes comparison of the heat flow ratios of each individual narrow side or wide side for a compensation for narrow-side conicity, particularly narrow-side copper plate conicity, relative to one another and for a correction in relation to the heat flows by way of the wide sides, and setting of a maximum possible casting speed as a function of melt temperature in the distributor and the respective material to be cast, or that if the changes in at least a part or all of the parameters for determination of the casting state are disposed outside a predetermined target interval, there is maintenance of a semi-automatic control of the angular adjustment of the chill mould narrow sides as well as the casting speed.
2. Method according to claim 1, characterised in that, after changeover to an automatic mode of operation has taken place, in the case of exceeding predetermined limit values of changes in the casting parameters an alarm (11.2) is triggered and the mode of operation is switched back to semi-automatic.
3. Method according to claim 1 and 2, characterised in that the dependence of the melt temperature in the distributor and the maximum possible casting speed for each steel group, such as, for example, "low carbon", "medium carbon" arid "high carbon", are established.
4. Method according to one of claims 1 to 3, characterised in that the heat flows per unit of area of the fixed side and also non-fixed side of the chill mould wide sides (W) are measured and that the heat flows per unit of area of the operating side (NO) and drive side (ND) of the chill mould narrow sides are measured, that the changes in the respectively measured values are averaged over a predetermined casting time interval and if changes in at least a part of the detected values are present within a predetermined limit interval there is changeover to an automatic mode of operation, wherein the limit interval is defined by:

   the change in the stopper movement is at most ± 2 mm/unit of time,

   the change in the height of the casting level is at most ± 5 mm/unit of time,

   the change in the heat flows of the chill mould wide sides is at most ± 0.10 MW/m² absolutely and relative to one another,

   the heat flow ratio of the narrow sides to the wide sides is as follows 0.9 > NO/W, ND/W > 0.4,

   and after changeover to automatic operation has taken place:

   regulation of the angular adjustment of the narrow side by means of control of adjusting cylinders so that the ratio of the heat flows of the narrow sides over the wide sides moves in the following limit interval 0.8 > NO/W, ND/W > 0.6,

   measuring the actual melt temperature in the distributor,

   regulation of the maximum permissible casting speed as a function of the melt temperature and alloy composition.
5. Method according to claim 4, characterised in that the correction of the angular adjustment of the narrow sides takes place automatically in steps each of 0.1 mm of adjusting action.
6. Method according to one of claims 1 to 5, characterised in that, apart from the alloy composition, the casting powder is included as a parameter in the regulation of the maximum permissible casting speed.
7. High-speed continuous casting plant for the casting of a metallic strip (1.7), for performance of the method according to one of claims 1 to 6, particularly for casting a slab, at casting speeds of at most 10 m/min with an oscillating chill mould (1), which comprises mutually opposite chill mould narrow sides (1.2.1, 1.2.2) and chill mould wide sides (1.3.1, 1.3.2), particularly of copper plates, which during the casting are controllable in their conicity with the help of adjusting cylinders (1.2.3), wherein the melt flows into the chill mould (1) by means of an immersion spout (1.5) or a nozzle from a distributor (6) and the distributor (1) has a movable stopper (6.1) or a slide closure for regulating the inflowing melt quantity, optionally with use of casting powder (1.6), with means for measuring the movement in casting level (9), with a continuous or discontinuous measuring device for measuring the melt temperature in the distributor (6.2), with means for measuring the actual casting speed (1.8) of the strip, particularly the slab, and a computer unit (10) for determining the changes in the casting process over a predetermined casting time interval and for comparison of the changes with predetermined limit values (10.1), characterised in that this further comprises:

   means for measuring the stopper or slide closure movement (6.1.1),

   means for measuring the wide side heat flows (7) from fixed side and non-fixed side,

   means for measuring the narrow side heat flows (8) from the operating side and the drive side,

   means (1.2.3) for changing the angular setting of the two chill mould narrow sides arranged conically relative to one another and

   means for changing the casting speed,

   wherein the means for changing the angular setting of the narrow side and the means for changing the casting speed are not only controllable independently in dependence on the result of the computer unit (10), but are also controllable semi-automatically.
8. Continuous casting plant according to claim 7, characterised by alarm means (11.2), which are activated on exceeding of the predetermined limit values by the calculated changes in the measured values, and means for switching back from automatic system to semi-automatic.
9. Continuous casting plant according to claim 7 or 8, characterised in that a joystick (11) is provided as operating means for semi-automatic control of the casting speed and/or the angular setting of at least one of the two chill mould narrow sides (12, 13).

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