US3886991A

US3886991A - Method and apparatus for controlling the withdrawal of heat in molds of continuous casting installations

Info

Publication number: US3886991A
Application number: US351772A
Authority: US
Inventors: Walter Meier; Werner Bruderer
Original assignee: Concast AG
Current assignee: SMS Concast AG
Priority date: 1972-04-18
Filing date: 1973-04-16
Publication date: 1975-06-03
Anticipated expiration: 1992-06-03
Also published as: BE798388A; AU470292B2; FI54067B; AU5460773A; DE2319323B2; FR2180902B1; FR2180902A1; DE2319323A1; GB1409947A; FI54067C; CA977930A; JPS5219808B2; JPS4921329A; ZA732632B; NL154132B; NL7305351A; CH552423A

Abstract

A method of, and apparatus for, controlling the withdrawal of heat from a cast strand by means of a cooling agent during the continuous casting of metals in continuous casting molds having cooling regions along the periphery of the mold and which cooling regions are separated from one another and thus constituting several ducts for said cooling agent, and wherein the withdrawn quantity of heat of each cooling region is measured. The quantity of withdrawn heat is compared with reference values for such quantity of heat which is to be withdrawn and which reference values are dependent upon the form or shape of the continuous casting mold. By virtue of this comparison operation there is determined contact of the skin or shell of the strand at the walls of the cooling region, and as a function of the deviations ascertained by the comparison operation there is controlled the quantity of heat withdrawn at least at one of the cooling regions which neighbors the measured region.

Description

United States Patent 1 Meier et al.

[ METHOD AND APPARATUS FOR CONTROLLING THE WITHDRAWAL OF HEAT IN MOLDS OF CONTINUOUS CASTING INSTALLATIONS [75] Inventors: Walter Meier, Winterthur; Werner Bruderer, Feldmeilen, both of Switzerland [73] Assignee: Concast AG, Zurich, Switzerland [22] Filed: Apr. 16, 1973 [211 App]. No.: 351,772

[30] Foreign Application Priority Data Apr. 18, 1972 Switzerland 5666/72 [52] US. Cl. 164/4; 164/82; 164/154; 164/283 M [51] Int. Cl B22d 11/02 [58] Field of Search 164/4, 82, 154, 283 M [56] References Cited UNITED STATES PATENTS 3,204,460 9/1965 Milnes l64/4 UX 3,478,808 ll/l969 Adams 164/4 3,630,270 12/1971 Adamec et al...... 164/283 M 3,786,856 1/1974 Nishikawa 164/4 FOREIGN PATENTS OR APPLICATIONS 241,058 4/1969 U.S.S.R .L r. 164/82 ELEMENTS MEASUREMENT ELEMENT ADJUSTMENT ELEMENTS June 3,1975

Primary Examiner-R. Spencer Annear Attorney, Agent, or Firm-Werner W. Kleeman [57] ABSTRACT A method of, and apparatus for, controlling the withdrawal of heat from a cast strand by means of a cooling agent during the continuous casting of metals in continuous casting molds having cooling regions along the periphery of the mold and which cooling regions are separated from one another and thus constituting several ducts for said cooling agent, and wherein the withdrawn quantity of heat of each cooling region is measured. The quantity of withdrawn heat is compared with reference values for such quantity of heat which is to be withdrawn and which reference values are dependent upon the form or shape of the continuous casting mold. By virtue of this comparison operation there is determined contact of the skin or shell of the strand at the walls of the cooling region, and as a function of the deviations ascertained by the comparison operation there is controlled the quantity of heat withdrawn at least at one of the cooling regions which neighbors the measured region.

6 Claims, 2 Drawing Figures I REGULATOR REFERENCE VALUE INDICATOR COMPUTER PATE-ETEDJUE3 m5 7 ELEMENTS REGULATOR MEASUREMENT ELEMENT 3 ci zfigewce INDICATOR ADJUSTMENT ELEMENTS OMPUTER METHOD AND APPARATUS FOR CONTROLLING THE WITHDRAWAL OF HEAT IN MOLDS OF CONTINUOUS CASTING INSTALLATIONS BACKGROUND OF THE INVENTION The present invention relates to a new and improved method of controlling the withdrawal of heat by means of a cooling agent during casting of metallic strands in continuous casting molds having cooling regions spaced from one another along the periphery of the mold thus constituting a number of ducts for said cooling agent, and wherein the withdrawn quantity of heat of each cooling region is measured, and this invention also pertains to a new and improved construction of apparatus for the performance of the aforesaid method.

In continuous casting installations for steel it is already known to the art to employ continuous casting molds having a number of cooling compartments or chambers for a cooling agent which are separately arranged about the periphery of the strand and extend in the direction of strand travel. in one such installation there is measured the quantity of heat withdrawn from the individual cooling compartments and this measured quantity of heat is then compared with a reference value. If the cast strand for some reason deviates from its desired path of travel, for instance owing to irregular or non-uniform shrinkage, then this strand will tend to bear in an irregular manner at the mold, and this will be reflected in terms of a change in the measured quantity of heat. In order to be able to correct the irregular contact with the mold walls, guide elements are arranged beneath the mold and such guide elements can be transversely displaced with respect to the path of travel of the strand. These guide elements are controlled as a function of the thermal deviation of the individual cooling compartments: in other words, by means of such displaceable guide elements the strand can be again brought back into its prescribed path of travel, insuring for uniform contact of the prevailing strand skin or shell along its periphery against the walls of the mold.

This prior art installation is designed in consideration of a predetermined casting speed which depends upon the casting parameters. For casting slab shapes, and prior to the start of the casting operation, there is undertaken an adjustment for instance of the narrow sides of the mold to a predetermined taper or conicity. This taper corresponds approximately to the shrinkage of the strand for a desired casting speed. However, since this taper cannot be adjusted during casting, whenever there occurs any deviation from the desired casting speed there are present the drawbacks which will be explained more fully hereinafter. By means of the aforementioned apparatus, it is attempted to uniformly bring into contact the strand along its periphery at all sides of the mold and therefore to insure for a uniform thickness of the strand skin over the periphery thereof.

More recent designs of continuous casting installations make provision for casting with different casting speeds at the same continuous casting installation. The aforedescribed apparatus has been found to be associated with decisive drawbacks when the installation is operated under these conditions. If, for instance, the casting speed is reduced, then the strand tends to prematurely raise away from the walls of the mold owing to the more intensified shrinkage or contraction according to the withdrawal of heat by means of a cooling agent, yet such mold walls possess a taper which is suitable for a predetermined casting speed. The foregoing phenomenon becomes noticeable through a change in the withdrawn quantity of heat at the cooling compartments. The lifting-off of the strand skin from the mold walls does not occur simultaneously over the entire periphery of the strand, and this explains why also the changes in the withdrawn quantities of heat are not of the same magnitude for all of the compartments. Since, however, the movable guide mechanism beneath the mold immediately corrects irregular cooling behavior in the mold by displacing the strand, the latter is shifted out of its desired position: that is to say, instead of improving the cooling behavior in the mold this cooling behavior with a change in the casting speed is impaired by the displaceable guide elements beneath the mold which are controlled by the quantities of heat measured at the cooling compartments. This can be clearly perceived in terms of the increase in the fissures appearing at the cast strand and the number of breakouts while increasing the casting speed and a decisively poorer withdrawal of heat owing to the poor contact which prevails between the strand skin and the walls of the mold. These defects in the casting operation result in reduced yield.

SUMMARY OF THE INVENTION Hence, it is a primary object of the present invention to provide an improved method of, and apparatus for, controlling the removal or withdrawal of heat in a mold in a manner rendering it possible to carry out casting operations at the same continuous casting installation throughout a large casting speed range with uniform quality and increased yield of the cast product, and without having to take into account the drawbacks of poor heat withdrawal in the mold, increased danger of metal breakout and irregular growth of the skin or shell of the strand and impaired geometric shape of the strand.

Yet a further significant object of the present invention relates to a new and improved method of, and apparatus for, controlling the withdrawal of heat at a continuous casting mold of a continuous casting installation in a manner overcoming the aforementioned drawbacks and limitations of the prior art proposals.

Now in order to implement these and still further objects of the invention, which will become more readily apparent as the description proceeds, the method of this development contemplates that through the comparison of the withdrawn quantities of heat with reference values for the withdrawn quantities of heat and which reference values are dependent upon the shape or format of the mold, there can be determined contact of the skin of the strand at the walls of the cooling regions of the mold, and that dependent upon the control deviation determined by the comparison operation there is controlled the withdrawal of the quantity of heat at least at one cooling region which neighbors a measured region.

By means of this control technique it is possible to carry out casting operations throughout a rather large casting speed range at a continuous casting mold, the taper or conicity of which has been set for a certain casting speed. Through the comparison of the quantities of heat withdrawn at the individual cooling regions with reference values dependent upon the shape of the mold, it is possible to determine contact of the strand skin at the walls of the cooling region along the entire mold and as a function thereof to control in at least one of the adjoining cooling regions the withdrawn quantity of heat by means of a cooling agent, until the cast strand shell or skin again bears in desired manner at the walls of the measured cooling region. As soon as the strand skin for each casting speed bears or contacts in the most suitable manner over the entire cooling region walls, it is possible to produce an improved surface of the cast strand and the solidified strand skin or shell grows more uniformly. As a result there can be prevented fissures in the cast product and the frequency of metal breakout is reduced to a minimum. The produced strand also exactly possesses the desired geometric cross-sectional configuration. Furthermore, in the mold there is always withdrawn the maximum possible quantity of heat without damaging the strand or the strand surface in any other way.

In the case of slab molds for casting of steel, it is advantageous if the quantities of heat withdrawn at the cooling regions of the conical or tapered narrow sides of the mold are measured and compared with reference values and as'a function thereof there is controlled the quantity of heat withdrawn at the cooling regions of the wide sides of the mold. This technique renders it possible to make really good use of the total cooling surface of the mold for random casting speeds.

Notwithstanding the above-described possibilities of controlling contact of the formed strand skin with the cooling surface of the mold at the narrow sides of the mold, it can happen that the strand skin does not come to bear in the desired manner at the regions of the corners of the mold and also at the wide sides of the mold. In such case it is advantageous if also the quantity of heat withdrawn at the cooling regions of the wide sides of the mold is measured, compared with the reference values, and the withdrawn quantity of heat of the cooling regions at the narrow sides controlled as a function thereof. While this technique requires a greater expenditure and a more complicated procedure, it does render possible, on the other hand, attaining the best possible control of the heat transfer at the entire cooling regions of the mold, particularly at the corner zones, where oftentimes the strand skin lifts-off the walls at the wide sides and also at the narrow sides of the mold and there exists an extremely non-uniform strand skin.

Particularly advantageous solutions can be realized in that the withdrawn quantities of heat at the controlled side, are controlled in sections starting from the measured side. Whether a greater quantity of heat is to be withdrawn at the regions located in the neighborhood of the measured side than at the remotely situated cooling regions, is dependent upon the properties of the mold and the shape of the cast strand. The sectionwise control in any case allows for accommodation of the withdrawn quantities of heat at the locations decisive for cooling at the measured cooling region.

As already explained above, the invention is not only concerned with the aforementioned method aspects, but also relates to a new and improved construction of apparatus for the performance of such method which is manifested by the features that the measurement devices for determination of the withdrawn quantites of heat by means of a cooling agent are coupled with a regulator having a connection line for transmitting the reference values from a computer, to which there is simultaneously delivered the measurement values of the withdrawn quantities of heat and which retains such measurement values as a function of the throughflow quantity of the cooling agent and the withdrawn quantity of heat respectively at the cooling regions adjoining the measured region and from such values determines the point serving as the reference value for the regulator which possesses the greatest difference of the withdrawn quantity of heat per unit of throughflow quantity of the cooling agent.

During normal casting operations there is attained an equilibrium condition between the constant casting speed and the constant cooling agent values, and which equilibrium condition insures that there will occur between the strand skin and the cooling region walls a heat exchange effect which is as advantageous as possible. Now if, for instance, the casting speed is reduced then at the narrow sides of the mold the quantity of heat withdrawn or removed via the useful mold surface and per unit of time becomes smaller. This reduction of the withdrawn quantity of heat is recorded by the regulator and the computer, whereupon the throughflowing quantity of cooling agent is reduced at the adjoining cooling regions. During this change in the quantity of cooling agent the computer simultaneously monitors the change in the quantity of heat withdrawn at the narrow sides of the mold. During such recording operation the computer determines that value having the greatest difference of the withdrawn quantity of heat per unit throughflow quantity of cooling agent. In so doing, the throughflow quantity units are to be chosen as a function of the desired regulation accuracy. As soon as this point has been reached, then there is introduced to the regulator as the reference value the new cooling agent quantitative value and there again occurs a new equilibrium condition between the casting speed and the cooling behavior at the mold which results in the most advantageous heat transfer.

BRIEF DESCRIPTION OF THE DRAWING The invention will be better understood and objects other than those set forth above, will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawing wherein:

FIG. 1 schematically illustrates a block circuit diagram of the control apparatus for controlling the removal of heat at a mold of a continuous casting installation; and

FIG. 2 is a graph showing the dependency of the withdrawn quantity of heat at the mold narrow sides during a change in the quantity of cooling agent e.g. water at the wide sides of the mold owing to a change in the casting speed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Describing now the drawing, in FIG. 1 there is designated by reference character 1 a slab mold of a continuous casting installation, this slab mold 1 essentially consisting of both of the

wide mold sides

2 and 3 and both of the narrow mold sides 4 and 5. These

mold walls

2, 3 and 4, 5 are provided with cooling compartments or chambers constituting ducts for the cooling agent, conveniently referred to hereinafter as the

cooling regions

7, 8 and 9, 10, respectively. Each of the

individual cooling regions

7, 8, 9 and 10 has operatively associated therewith cooling agent infeed and withdrawal conduits or lines 12, and the cooling agent or coolant is typically water. At the water infeed and withdrawal lines of the narrow mold sides 4 and 5 there are operatively connected measurement elements or

devices

14 and 15 for determining the quantity of with drawn or removed heat. The water infeed and withdrawal lines 12 of the

wide sides

2 and 3 of the mold 1 are equipped with adjustment or

setting elements

16, 17, and 18, 19 respectively for regulating the water quantity. The data determined by the

measurement elements

14 and 15 is delivered through the agency of connection lines 25 to a regulator 20 and at the same time also to a computer 30. The

adjustment elements

16, 17, 18 and 19 are controlled by the regulator 20 through the agency of the connection lines 24. The regulator 20 encompasses a function transmitter 21, a comparator 22 and a reference value indicator 23. The reference value indicator 23 receives the momentary reference values via a connection line 26 from the computer 30. The computer 30 is operatively connected via connection lines 27 with suitable and therefore not particularly illustrated date input devices for the infeed of relevant information concerning the mold, the taper or conicicity, the quality of the steel, the temperature of the steel, and so forth.

Prior to the casting operation, both of the narrow mold sides 4 and 5 are set to a certain taper or conicicity corresponding to an average or mean casting speed, in other words, the spacing between the narrow sides 4 and 5 of the molds is less at the outlet end of the mold 1 than at the inlet or pour-in side of such mold. The quantities of water for the narrow mold sides 4, 5 and for the

wide mold sides

2, 3 and corresponding to such average or mean casting speed and the corresponding mold taper or conicicity, are calculated or determined by trial, stored at the computer 30 and selected thereby and delivered to the

cooling regions

7, 8, 9 and 10. Now if during the casting operation the casting speed deviates, for instance due to defective operation of a stopper or clogging of the pouring or outlet opening, from the average casting speed, then the formed strand skin will bear more intensely or less intensely, as the case may be, at the walls 6 of the cooling regions 9, of the narrow mold sides 4, 5. Due to this change in the contact of the strand skin, the quantity of heat withdrawn at the

cooling regions

9 and 10 also becomes correspondingly greater or smaller. Such change is determined by the measurement elements or

devices

14 and 15 and indicated via the connection lines 25 at the regulator as well as at the computer 30. At the comparator 22 there is compared the measurement value with the reference value received from the reference value indicator or transmitter 23 and via the function transmitter 21 there is controlled the water quantity at the adjoining

cooling regions

7, 8 of the

wide mold sides

2, 3 by means of the

adjustment elements

16, 17, 18 and 19. Since as a result the shrinkage of the strand again will be influenced, there is brought about a change in the contact or bearing of the strand at the walls 6 of the

cooling regions

9, 10 of the narrow sides 4, 5 of the mold, and this again is ascertained by the

measurement elements

14, 15 and delivered to the regulator 20 as well as the computer 30. The regulator 20 now controls the quantity of cooling water delivered to the

wide sides

2, 3 of the mold for such length of time until the quantities of heat withdrawn at the

cooling regions

9, 10 coincide with the reference values prescribed by the reference value indicator or transmitter 23. At the same time, however, the computer retains such changes of the quantities of heat withdrawn from the

cooling regions

9, 10 as a function of the quantity of water flowing through the

cooling regions

7, 8 and from these values determines that point having the greatest difference in the withdrawn quantity of heat per unit of throughput quantity of cooling agent. This value is then introduced via the connection line 26 to the reference value indicator 23 in the form of a new reference value, this operation simultaneously occurring together with the regulation operation.

In FIG. 2 there is plotted a possible course of such values, and specifically in terms of a reduction in the casting speed. Now there has been plotted without dimensions along the abscissa of the graph of FIG. 2 the water quantity 38 which flows through the

cooling regions

7, 8 of the mold

wide sides

2, 3. Along the ordi nate 36 of this graph there has also been plotted without any dimensions the heat quantity 37 withdrawn at the

cooling regions

9, 10 of the mold narrow sides 4, 5. Such withdrawn heat quantity is normally related to the useful mold surface.

During normal casting operations with a predetermined average or mean casting speed, there is associated therewith a certain water quantity 43 which flows through the

cooling regions

7 and 8 of the

wide sides

2 and 3 of the mold, and which water quantity corresponds to a predetermined water quantity 40 withdrawn at the

cooling regions

9, 10 of the narrow sides 4, 5 of the mold. Now if the casting speed is reduced, then the wide sides of the strand are more intensely cooled, with the result that such are subjected toa correspondingly more intense shrinkage and raise-off sooner from the narrow sides of the mold. As a result, less heat is withdrawn at the mold narrow sides 4, 5, and this becomes apparent in terms of a reduction in the withdrawn quantity of heat from 40 to 41. As a function thereof, the regulator 20 begins to control the withdrawn quantity of heat and the water quantity at the

wide sides

2, 3, that is to say, with decreasing casting speed the water quantity at the

wide sides

2, 3 of the mold is reduced. Due to the reduced withdrawal of heat at the

wide sides

2, 3 of the mold the strand shrinks less along the regions of the wide sides of the mold, so that it again bears better at the narrow sides of the mold and the withdrawn quantity of heat at the narrow sides of the mold again increases. This increase in the withdrawn heat quantity 37 during the reduction of the throughflowing water quantity 38 is stored or retained at the computer 30, with the result that the withdrawn heat quantity 37 per unit of throughflow quantity 38 of cooling water at the beginning increases much more markedly until it has reached its maximum value and thereafter becomes less.

The computer 30 then determines the point of greatest increase in the withdrawn heat quantity 37 per unit of throughflow quantity 38 of cooling water and gives such determined point in the form of a new reference value 42 for the heat quantities which are to be withdrawn at the narrow sides 4, 5 to the reference value transmitter 23. The withdrawn heat quantity 42 is again associated with a predetermined water quantity 44 which flows through the

cooling regions

7, 8 of the

wide sides

2, 3 of the mold. This condition is now maintained by the regulator 20 until there occurs a renewed change in the casting speed.

A more precise operation of the control can be realized in that the measurement values determined by the measurement elements or

devices

14, 15 associated with the

cooling regions

9, 10 of the mold narrow sides 4 and 5 are individually introduced into the computer 30 and the

cooling regions

7, 8 of the mold

wide sides

2, 3 are also individually controlled. In FIG. 1 there are shown for each mold side two cooling regions. The number of cooling regions per mold side can, however, be increased depending upon requirements. With such embodiment of the control, there also can be measured an irregular lift-off or contact of the strand skin at a respective one of the walls of the

cooling regions

9 and 10 of the mold narrow sides 4, 5. Independent thereof there are controlled the water quantities of the

cooling regions

7 or 8 of the

wide sides

2 and 3 and which cause this irregular strand lift-off, in order to correct the heat quantity withdrawn at the measured cooling region of the narrow sides. If, for instance, a reduction in the withdrawn heat quantity is only determined at the cooling region 10 of the narrow sides 4, then initially there is only controlled the water quantity of the adjoining cooling region 8 of the wide side 3. If this control of the cooling region 8 of the wide side 3 of the mold is not sufficient, then it is possible to additionally also control the cooling region 7 of the wide side 3.

With a sub-division of the

wide sides

2, 3 of the mold into more than two cooling regions, it is possible to progressively accurately control the heat quantity removed at the mold narrow sides 4, 5. In so doing, for instance with a change in the withdrawn heat quantity at the cooling region 9, the withdrawn heat quantity at the adjoining wide sides, in this case at the wide sides consisting of more than two cooling regions, is controlled in sections beginning from the cooling region 9. As a function of the desired cooling operation, it is possible to, however, also beginning from the center of the controlled sides, carry out the control operation in sections towards the measured sides.

If the formed strand possesses along its periphery a particularly uniform thickness of the strand skin and in the direction of the lengthwise axis of the mold a certain growth of such skin or shell, then there are associated with the

cooling regions

9, 10 of the narrow sides 4, 5 additional

non-depicted adjustment elements

16, 17, 18 and 19 for regulating the water quantity and the

cooling regions

7, 8 of the

wide sides

2, 3 have associated therewith measurement elements 14, for the determination of the withdrawn heat quantities. All measurement data is then simultaneously transmitted via connection lines to the regulator 20 and the computer and via appropriate connection lines 24 it is possible to control with the aid of the

adjustment elements

16, 17, 18 and 19 the throughflowing water quantity for all cooling regions. This renders possible correction of the lift-off or too pronounced contact of the formed strand skin at the

wide sides

2, 3 as well as at the narrow sides 4, 5 of the mold. As a general rule, the formed strand skin bears in desired manner against the

wide sides

2, 3 of the mold owing to the ferrostatic pressure. It is also possible that the strand does not bear in the desired fashion only at the corner regions of the

wide sides

2, 3 of the mold, something which can be particularly ascertained in the case of a small ratio in the length of the

wide sides

2, 3 with respect to the length of the narrow sides 4, 5 of the mold. In such case the water quantity flowing through the

cooling regions

9, 10 of the narrow sides 4, 5 can be changed until at the adjoining

cooling regions

7, 8 of the

wide sides

2, 3 there is again ascertained the desired withdrawn quantity of heat. Such type control requires, however, a considerably greater expenditure in the design of the regulator 20 and the computer 30.

While there is shown and described present preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto, but may be otherwise variously embodied and practiced within the scope of the following claims.

Accordingly, what is claimed is:

l. A method of controlling the withdrawal of heat from a cast strand by means of a cooling agent during continuous casting of metals, comprising the steps of casting the strand in a continuous casting mold having several cooling regions adjacent one another around the periphery of the mold and constituting several ducts for the cooling agent, measuring the quantity of heat withdrawn at least at given ones of the cooling regions, comparing the withdrawn quantities of heat with reference values for such quantities of heat which are to be withdrawn and which reference values are dependent upon the shape of the mold, to thereby determine contact of the skin of the strand against the walls of the mold, and as a function of the deviations of the withdrawn quantities of heat and the reference values of such quantities of heat whichare to be withdrawn determined by the comparison operation controlling the quantity of heat withdrawn at least at one cooling region adjoining a measured region so as to control the contact of the strand skin and mold wall.

2. The method as defined in claim 1, particularly for a slab casting mold, including the step of measuring the quantities of heat withdrawn at the cooling regions of the narrow sides of the mold and comparing such with reference values, and as a function of any deviation between the quantities of heat withdrawn at the cooling regions of the narrow sides of the mold with said reference values controlling the quantities of heat withdrawn at the cooling regions of the wide sides of the mold.

3. The method as defined in claim 1, including the step of measuring the quantities of heat withdrawn at the cooling regions of the wide sides of the mold and comparing such with said reference values and as a function of the deviation in the comparison of the quantities of heat withdrawn at the cooling regions of the wide sides of the mold with said reference values controlling the quantities of heat withdrawn at the cooling regions of the narrow sides of the mold.

4. The method as defined in claim 2, wherein the withdrawn quantities of heat at the controlled side are controlled in sections starting from the measured side.

5. The method as defined in claim 3, wherein the withdrawn quantities of heat at the controlled side are controlled in sections starting from the measured side.

6. Apparatus for controlling the withdrawal of heat from a cast strand by means of a cooling agent during continuous casting of metals at a continuous casting installation, comprising a continuous casting mold having cooling regions separated from one another along the periphery of the mold and constituting several ducts for the cooling agents, means for controlling the cooling of the cast strand in order to control the strand skin-mold measurement values as a function of the throughflow quantity of cooling agent and the withdrawn quantity of heat at the cooling regions adjoining the measured regions, and said computer determining from such values the point having the greatest difference between the withdrawn quantity of heat per unit of such throughflow quantity of cooling agent and which point serves as anew reference value for the regulator as concerns the heat quantities to be withdrawn.

Claims

1. A method of controlling the withdrawal of heat from a cast strand by means of a cooling agent during continuous casting of metals, comprising the steps of casting the strand in a continuous casting mold having several cooling regions adjacent one another around the periphery of the mold and constituting several ducts for the cooling agent, measuring the quantity of heat withdrawn at least at given ones of the cooling regions, comparing the withdrawn quantities of heat with reference values for such quantities of heat which are to be withdrawn and which reference values are dependent upon the shape of the mold, to thereby determine contact of the skin of the strand against the walls of the mold, and as a function of the deviations of the withdrawn quantities of heat and the reference values of such quantities of heat which are to be withdrawn determined by the comparison operation controlling the quantity of heat withdrawn at least at one cooling region adjoining a measured region so as to control the contact of the strand skin and mold wall.