• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
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    • 专利摘要:
    The invention relates to a method for cooling a metallic strand (22) in a continuous casting plant (2, 52), in which by one or more coolant nozzles (38) of successive Düsenein units in strand conveying direction (26) cooling capacities on the strand (28). 22). In order to achieve efficient cooling of the strand (22), it is proposed that the cooling capacities on an arbitrarily small surface segment of the strand (22) in the strand conveying direction (26) alternate.
    公开号:AT518450A1
    申请号:T50223/2016
    申请日:2016-03-17
    公开日:2017-10-15
    发明作者:Mirko Javurek Dr
    申请人:Primetals Technologies Austria GmbH；
    IPC主号:
    专利说明:

    description
    Method and cooling device for cooling a metallic strand
    The invention relates to a method for cooling a metallic strand in a continuous casting plant, in which cooling capacities are performed on the strand by one or more coolant nozzles of successive nozzle units in the strand conveying direction.
    In the continuous casting of metals, a metallic melt is fed into a continuous casting plant of a (water) cooled mold. In the mold, the melt is solidified at least in its edge region and usually continuously - already supplied in the form of a strand - from the mold on a side of the mold arranged strand guide the continuous casting and conveyed through the strand guide.
    When leaving the mold, the strand has a solidified shell, the majority of its cross-section is still liquid. In the region of the mold outlet, the strand has a surface temperature of the order of 1000 ° C. For further cooling and solidification of the strand, a coolant is usually applied to the strand surface in the continuous casting plant by means of coolant nozzles.
    JP 63-112058 A describes a method in which surface temperatures of a metallic strand are adjusted by heating and cooling operations in successive cooling zones of a continuous casting plant in such a way that they change from cooling zone to cooling zone in alternation or below the transition temperature of austenite to ferrite exceed the transformation temperature of ferrite to austenite.
    An object of the invention is to provide a method with which an efficient cooling of a metallic strand can be achieved.
    This object is achieved by a method of the initially mentioned type, in which, according to the invention, the cooling capacities at an arbitrarily small surface segment of the strand alternate in the strand conveying direction.
    Advantageous developments of the method according to the invention are each the subject of dependent claims and the following description.
    The invention is based on the consideration that in continuous casting plants typically several consecutive in the strand conveying direction coolant nozzles (or successive rows of coolant nozzles) act on the strand surface each with the same amount of coolant, for example, because these coolant nozzles / nozzle rows are combined to form a cooling zone in which the coolant nozzles be acted on the input side with the same flow of coolant. Such a coolant supply through the coolant nozzles / nozzle rows of a cooling zone which is constant in the direction of the flow of the strand causes the coolant nozzles / nozzle rows in the strand conveying direction to accomplish the same or approximately the same cooling capacity on the strand.
    Furthermore, the invention is based on the finding that a vapor film usually forms on the strand surface, which stabilizes the cooling effect. If the strand surface is exposed to a high amount of coolant, such a strong cooling of the strand surface may occur in the area of the impinging coolant that the vapor film collapses. This in turn can cause the cooling effect increases unintentionally strong. Typically, the collapse of the vapor film is a process that occurs abruptly when the strand surface is a certain critical one
    Temperature (the so-called "Leidenfrosttemperatur") falls below.
    The collapse of the vapor film may result in a certain range of strand surface temperatures not being achievable by varying the amount of coolant applied to the strand surface by the individual coolant nozzles. If the strand surface is acted upon by the coolant nozzles in each case with a coolant quantity which is in the range of the coolant quantity at which such a collapse of the vapor film occurs, a slight change in this coolant quantity can cause an unintentionally strong temperature change of the strand surface. In such a case, the strand surface becomes too cold with a slight increase in the amount of coolant, or too hot with a slight decrease in the amount of coolant.
    As mentioned above, the invention proposes that the cooling powers performed by the coolant nozzles on an arbitrarily small surface segment of the strand alternate in the strand conveying direction. In this way, even such strand surface temperatures can be set, which can not be achieved at constant in the direction of flow conveying coolant.
    In the present case, the amount of heat (or thermal energy) per unit time which is withdrawn from a surface segment of the strand can be understood as cooling power.
    The fact that the cooling powers alternate in the strand conveying direction, it can be achieved that the strand surface is first cooled more, then is cooled weaker, then again cooled more, then cooled again weak and so on. By setting an appropriate alternation pattern, the average strand surface temperature can be set to a desired value.
    The arbitrarily small surface segment may be understood as an imaginary section of the strand surface, which may have any desired shape. The said surface segment of the strand may have, in particular transversely to the strand conveying direction, an arbitrarily small dimension which, for example, corresponds to a fraction of a width of one of the nozzle units. Preferably, said surface segment is a surface segment moving along with the strand.
    Furthermore, the strand conveying direction can be understood as the direction in which the strand is conveyed / guided in the continuous casting plant. Conveniently, the strand conveying direction is predetermined by a strand guide of the continuous casting plant.
    The fact that the cooling capacities alternate in the strand conveying direction can be understood to mean that the amounts of the cooling capacities in the strand conveying direction decrease or increase more than once in alternation. The cooling powers thus alternate expediently with regard to their amount in the strand conveying direction.
    The "achievement of cooling performance on the strand" can be understood as a cooling of the strand or a dissipation of thermal energy from the strand surface, in particular by applying a coolant to the strand surface.
    The invention is not limited to the cooling performances alternating (only) between values. In principle, the cooling capacities can alternate between more than two values, ie alternately decrease or increase.
    In a preferred manner, the alternating in the strand conveying direction cooling performance by alternating amounts of coolant, which are applied to the arbitrarily small surface segment, causes. In other words, the alternating cooling in Strangför device cooling performance can be achieved by alternating the amounts of coolant that are applied from the nozzle units of the continuous casting plant on the strand surface, in the strand conveying direction.
    The coolant quantity can be understood to be a mass or a volume of the coolant which is applied to the strand surface per unit of time, in particular based on a defined surface section of the strand. That is, the amount of refrigerant may be a measurable quantity in kg / s or 1 / s (or kg / (m2s) or l / (m2s)). Alternatively, the coolant quantity can be understood to be a mass or a volume of the coolant which is applied to the strand surface within a predetermined period of time, in particular based on a defined surface section of the strand. In the latter case, the amount of coolant may be a measurable quantity in kg or 1 (or in kg / m2 or 1 / m2).
    The fact that the coolant quantities alternate in the strand conveying direction can be understood to mean that the amounts of the coolant quantities in the strand conveying direction decrease or increase more than once in alternation. The predetermined quantities of coolant thus suitably alternate in terms of their amount.
    The strand may in particular be a steel strand. Alternatively, the strand may be a copper or aluminum strand. Preferably, the strand is a continuous strand.
    Furthermore, the strand to be cooled may have a shell thickness of a few millimeters to several centimeters, in particular in the region of a mold exit. For shell thicknesses in the range of a few millimeters, the method proves to be particularly advantageous, since the problem of collapsing, stabilizing vapor film is particularly pronounced here. Expediently, the shell thickness increases with increasing cooling time or with increasing distance from the mold outlet.
    The coolant that is applied to the strand surface, for example, be water or air - or water as a component, as in a water-air mixture containing. In principle, other substances can also be used as the coolant or coolant component.
    Furthermore, the strand guide of the continuous casting plant can have a bending, a circular and / or a straightening zone. The nozzle units can in principle be arranged in any of these zones. Conveniently, the nozzle units are elements of a cooling device of the continuous casting plant.
    Said nozzle units may be in the strand conveying direction, in particular directly consecutive nozzle units. Two nozzle units can then be considered to be directly consecutive in the strand conveying direction when the two nozzle units are adjacent in the strand conveying direction or no other nozzle units are arranged in the strand conveying direction between these two nozzle units.
    The quantities of coolant advantageously alternate in the strand conveying direction in the case of several, in particular at least four, successive nozzle units.
    Furthermore, the coolant quantities in the strand conveying direction can alternate directly or indirectly.
    According to a preferred variant of the invention, the coolant quantities in the strand conveying direction alternate directly, so that the quantities of coolant in the conveying direction of the strand decrease or increase alternately in each case after one nozzle unit. In this case, the amounts of coolant in the strand conveying direction alternately decrease or increase from one nozzle unit to the next.
    According to another advantageous variant of the invention, the coolant quantities in the strand conveying direction alternate indirectly, so that the coolant quantities in the strand conveying direction decrease or increase alternately after every n nozzle units. Here, n is expediently a natural number greater than 1. In the case of direct alternation of the coolant quantities, however, n would be equal to 1.
    In a preferred manner, the coolant quantities in the strand conveying direction alternate between a first predetermined / adjustable value and a second predetermined / adjustable value. That is, the respective amount of coolant may take either the first or the second value. Such a kind of alternation can be realized in a particularly cost-effective manner in terms of control engineering.
    Preferably, the first value is greater than the second value.
    In an advantageous variant of the invention, the second value is zero. In another advantageous variant of the invention, the second value is greater than zero. Conveniently, the first value is set / adjusted as a function of a desired surface temperature of the strand. It is also expedient if the second value is predetermined / adjusted as a function of a desired surface temperature of the strand.
    Furthermore, it is possible for the coolant quantities in the strand conveying direction to alternate between more than two values, in particular between three values.
    According to an advantageous embodiment of the invention, the nozzle units each have at least one coolant nozzle. Appropriately, the coolant is applied to the strand surface using the coolant nozzles, in particular sprayed. The coolant can emerge in particular in the form of a cone ("coolant cone") from the respective coolant nozzle.
    The coolant nozzles may differ in the strand conveying direction alternately in their respective structural design from each other. That is, the coolant nozzles may be different from each other in the strand conveying direction with respect to their respective shape and / or at least one of their respective dimensions, such as their respective exit diameter. In particular, adjacent coolant nozzles, that is to say in the strand conveying direction directly consecutive coolant nozzles, can differ from one another in terms of their design configuration in the strand conveying direction.
    Different outlet diameters can be realized in the coolant nozzles, for example by means of exit aperture. The coolant nozzles can be equipped with exit orifices which differ in pairs, for example in the strand conveying direction, in particular with regard to their respective opening diameter. Furthermore, it is possible for the coolant nozzles in the strand conveying direction to be alternately configured in each case with exit aperture or without exit aperture. That is, exit apertures may be provided, for example, in the strand conveying direction at every other nozzle unit, while the coolant nozzles of the nozzle units positioned therebetween may be configured without exit apertures.
    Existing continuous casting plants can be retrofitted with the aid of exit orifices in a cost-effective manner, so that in such plants, alternating amounts of coolant can be realized cost-effectively in the strand conveying direction.
    Alternatively or additionally, the nozzle units may each have an adjusting device. Conveniently, the adjustment of the respective nozzle unit is prepared to a quantity of coolant which is applied by the respective nozzle unit to the strand set, in particular special about a position / position of the adjustment. Furthermore, it is expedient if the position / position of the adjusting device is controlled by means of a control unit.
    The adjusting device of the respective nozzle unit may, for example, be a control valve, which is arranged in particular on the input side of the at least one coolant nozzle of the respective nozzle unit. The respective control valve is expediently adapted to throttle and release a coolant supply to the at least one coolant nozzle of the respective nozzle unit.
    In particular, such a control valve can be throttled to a zero flow rate or the control valve can be repeatedly opened and closed ("pulsed cooling") so as to adjust the amount of coolant In the case of pulsed cooling, for example, the pulse durations of the control valves can alternate in the strand conveying direction.
    In a further advantageous embodiment of the invention, the adjusting device of the respective nozzle unit may be an adjustable shielding unit, which is arranged in particular between the strand and the at least one coolant nozzle of the respective nozzle unit. At least a portion of the coolant exiting the at least one coolant nozzle of the respective nozzle unit may impact the associated shielding unit rather than the strand surface so that that portion of the coolant does not strike the strand surface. The respective shielding unit may, for example, comprise at least one shielding plate, which can be displaced in particular by means of a servomotor.
    In principle, it is possible that the nozzle units each have a plurality of adjusting devices. One of the multiple adjusters may be configured, for example, as a control valve. Another of the multiple adjustment devices may be configured as a shielding unit, for example.
    For example, the nozzle units each have exactly one coolant nozzle. In a preferred embodiment of the invention, the nozzle units each have a row, in particular in each case exactly one row, of coolant nozzles which follow one another transversely to the strand conveying direction. This allows a uniform coolant loading of the strand across its width.
    Preferably, the individual coolant nozzles of the respective nozzle unit are acted on at their entrances with the same coolant flow. Furthermore, the nozzle units may each have a common adjustment device for their coolant nozzles.
    In an advantageous embodiment of the invention, a surface temperature of the strand is determined. For this purpose, a temperature measuring device is expediently used. It is particularly preferred if the temperature measuring device is adapted to measure the surface temperature of the strand without contact. The temperature measuring device may be, for example, a pyrometer.
    Advantageously, the cooling capacities are set by means of a control unit, in particular by means of the aforementioned control unit, as a function of the determined surface temperature and / or a predetermined / adjustable surface temperature setpoint. Preferably, the cooling powers are adjusted by means of the control unit as a function of the difference between the determined surface temperature and the predetermined / adjustable surface temperature setpoint. In this way, the cooling capacities can be set / adjusted in such a way that the surface temperature of the strand reaches said setpoint value or at least approaches it.
    An advantageous development of the invention provides that the nozzle units are elements of the same cooling zone of Kühlein direction. The cooling zone can have, among other things, a common coolant pump and / or a common coolant supply line for the nozzle units.
    In addition, in addition to the said nozzle units, the cooling zone can also have further nozzle units which follow one another in the direction of strand delivery and which expediently act upon the strand surface in each case with a predetermined amount of coolant. The amounts of coolant applied to the strand surface by these nozzle units may be constant in the strand conveying direction. Furthermore, these nozzle units can be arranged with respect to the strand conveying direction in front of or behind the first-mentioned nozzle units.
    Furthermore, the cooling device may have a plurality of such in the strand conveying direction consecutive cooling zones.
    As previously mentioned, the cooling capacities alternating in the strand conveying direction are preferably effected by alternating amounts of coolant applied by the nozzle units to the arbitrarily small surface segment. Except by alternating amounts of coolant that are applied to the arbitrarily small surface segment, the alternating cooling capacities can additionally (ie in combination with alternating amounts of coolant) or alternatively (ie instead of the alternating amounts of coolant) effected / achieved in other ways.
    For example, the alternating in the strand conveying direction cooling performance can be effected by alternating coolant temperatures of the applied to the arbitrarily small surface segment coolant. That is, a first nozzle unit may apply the coolant to the strand at a first coolant temperature. A nozzle unit following this nozzle unit in the strand conveying direction may apply the coolant to the strand at a second coolant temperature different from the first coolant temperature. One of the latter nozzle unit in strand conveying direction following nozzle unit can apply the coolant with the first coolant temperature on the strand and so on.
    Furthermore, the cooling capacities alternating in the strand conveying direction can be effected by different coolant media applied to the arbitrarily small surface segment. In this case, the coolant media alternately alternate in the strand conveying direction. The different coolant media are advantageously different from each other in terms of their Wärmekapizität.
    In addition, the alternating in the strand conveying direction cooling capacities can be effected by alternately applied to the arbitrarily applied to the arbitrarily small surface segment coolant spray densities. The coolant spray density can be understood as meaning a quantity of coolant applied to the strand, based on a surface unit. Different coolant spraying densities can be achieved, for example, by virtue of their nozzle nozzles having a different outlet diameter from their coolant nozzles than from another nozzle unit of the continuous casting plant and / or at a different distance from the strand.
    Furthermore, the invention relates to a cooling device for cooling a metallic strand in a continuous casting plant, in particular according to a method according to one of claims 1 to 13, comprising a plurality of strand conveying direction successively arranged nozzle units each having one or more coolant nozzles, which are adapted to cooling services on the Strand to accomplish.
    In the cooling device according to the invention, the nozzle units are adapted to accomplish the cooling performance on an arbitrarily small surface segment of the strand in the strand conveying direction alternately.
    Furthermore, the cooling device according to the invention may be the cooling device mentioned above in connection with the method.
    Furthermore, the advantageous features mentioned above in connection with the method can also relate to advantageous developments of the cooling device according to the invention.
    The nozzle units of the cooling device may each have an adjusting device for adjusting a quantity of coolant. Advantageously, the adjusting devices are adjustable in such a way that the quantities of coolant which are applied to the strand surface by the nozzle units alternate in the strand conveying direction.
    Alternatively or additionally, the nozzle units in the strand conveying direction may alternately differ from one another in their respective structural design. The alternating design configurations of the nozzle units (or their coolant nozzles) can cause the quantities of coolant applied to the strand by the nozzle units to alternate in the direction of strand delivery.
    It can thus be advantageously achieved by means of the adjusting devices and / or by means of the alternating constructive configurations that the predetermined quantities of coolant - and consequently the cooling powers performed by the nozzle units on the strand - alternate in the strand conveying direction.
    In addition, the invention is directed to a continuous casting plant having the cooling device according to the invention. In addition to the cooling device, the continuous casting plant may have further elements, such as a metallurgical pan, a distribution basin, a mold and / or a strand guide.
    The previously given description of advantageous embodiments of the invention contains numerous features, which are given in the individual subclaims partially summarized in several. However, these features may conveniently be considered individually and combined into meaningful further combinations. In particular, these features can be combined individually and in any suitable combination with the method according to the invention and the cooling device according to the invention. Thus, process features, objectively formulated, can also be seen as a property of the corresponding device unit and vice versa.
    Although some terms are used in the specification or in the claims in each case in the singular or in conjunction with a number word, the scope of the invention for these terms should not be limited to the singular or the respective number word.
    The above-described characteristics, features, and advantages of the invention, as well as the manner in which they will be achieved, will become clearer and more clearly understood in connection with the following description of the embodiments of the invention, which will be described in connection with the drawings. The embodiments serve to illustrate the invention and do not limit the invention to the combinations of features specified therein, not even with respect to functional features. In addition, suitable features of each embodiment may also be explicitly considered isolated, removed from one embodiment, incorporated into another embodiment to supplement it, and combined with any of the claims.
    1 shows a schematic representation of a Stranggussanla ge with a cooling device; 2 shows a section through the continuous casting plant of FIG. 1 along the sectional plane II-II there; 3 shows a schematic representation of another
    Continuous casting plant with a cooling device; 4 shows a diagram with three graphs, which in each case exemplarily represent the course of a strand surface temperature as a function of a length coordinate in the strand conveying direction, and FIG. 5 shows a diagram which, in addition to the three graphs from FIG. 3, contains a fourth graph which shows the course of a strand surface temperature as an example a length coordinate reproduces in the strand conveying direction. 1 shows a continuous casting plant 2 in a schematic representation. The continuous casting plant 2 can be, for example, a plant for casting steel slabs.
    The continuous casting plant 2 comprises inter alia a pan 4 with an outlet pipe 6. The continuous casting plant 2 further comprises a distribution basin 8 arranged below the pan 4 with a pouring pipe 10 and a stopper 12 arranged in the distribution basin 8.
    In addition, the continuous casting plant 2 comprises a mold 14, which has four water-cooled Kokillenplatten 16 made of copper and has a rectangular cross-sectional shape. In FIG. 1, only two of the four mold plates 16 are visible.
    In addition, the continuous casting plant 2 comprises a plurality of driven transport rollers 18 for guiding and supporting a strand, which form elements of a strand guide of the continuous casting plant 2.
    In addition, the continuous casting plant 2 a figuratively not shown following aggregate, such as a flame cutting machine, on.
    In the pan 4 is liquid steel 20, which is introduced via the outlet pipe 6 in the distribution basin 8. From the distribution basin 8 in turn, the liquid steel 20 is introduced via the pouring tube 10 into the mold 14, wherein a mass flow of the steel 20 flowing into the mold 14 is controlled by means of the plug 12.
    In the mold 14, the steel 20 cools at its contact surfaces with the water-cooled mold plates 16 and solidifies, so that the steel 20 emerges from the mold 14 in the form of a strand 22 with a rectangular cross-section.
    When exiting the mold 14, the strand 22 has a solidified shell of a few millimeters thickness, while a large part of its cross section is still liquid. Its surface temperature is on the order of about 1000 ° C.
    By means of the transport rollers 18 emerging from the mold 14 strand 22 is removed and led to the aforementioned (figuratively not shown) follower unit, by means of which the strand 22 is cut, for example in the form of slabs and then removed. Alternatively, the strand 22 could be directly further processed by a (different) follower unit, for example a rolling stand of a cast-rolling compound, without first being cut into slabs.
    Furthermore, the continuous casting plant 2 has a cooling device 24 for cooling the strand 22.
    The cooling device 24 comprises sixteen in the strand conveying direction 26 successively arranged nozzle units 28 for cooling the strand 22 from a first (according to the drawing obe ren) page. Of these nozzle units 28, four nozzle units 28 consecutive in the strand conveying direction 26 each belong to a common cooling zone 30 of the cooling device 24. That is, said sixteen nozzle units 28 are divided into four cooling zones 30 each having four nozzle units 28.
    Each of these cooling zones 30 has its own coolant pump 32, a main coolant supply line 34 connected to its coolant pump 32, from which branch off four individual coolant supply lines 36 which are each connected to one of the nozzle units 28.
    The nozzle units 28 each have a series of several transverse to the strand conveying direction 26 successive coolant nozzles 38 (see FIG 2). In addition, the nozzle units 28 each have an electrically controllable control valve 40 in the present embodiment.
    Furthermore, the cooling device 24 has a control unit 42. Said control valves 40 are connected to the control unit 42 via data lines (not shown in the figures) and are controlled by the control unit 42.
    In addition, the cooling device 24 comprises sixteen nozzle units 28, arranged successively in the strand conveying direction 26, for cooling the strand 22 from a second (marked lower side), which lies opposite the first side. These nozzle units 28 also each have a control valve 42 connected to the control valve, wherein the control valves of these nozzle units 28 are not shown for clarity better figurative.
    Of the last-mentioned sixteen nozzle units 28, four nozzle units 28 succeeding each other in the strand conveying direction 26 belong to a common cooling zone. Each of these cooling zones also has its own coolant pump, a main coolant supply line connected to its coolant pump, from which four individual coolant supply lines branch off, these elements not being shown figuratively for the sake of clarity.
    The number of nozzle units 28 per strand side - in the present case sixteen - and their numerical distribution in several cooling zones 30 - in the present case four cooling zones 30 per strand side - is chosen only as an example. That is, the continuous casting plant 2 could basically have a different number of nozzle units 28 and / or a different number of cooling zones 30.
    In addition, the cooling device 24 comprises a temperature measuring device 44, for example a pyrometer, for non-contact temperature measurement of a surface temperature of the strand 22. The temperature measuring device 44 is connected to the control unit 42 via a data line 46.
    In principle, the cooling device 24 can have a plurality of such temperature measuring devices. For example, at least one temperature measuring device can be provided both on the first side of the strand 22 and on the second side of the strand 22. While the strand 22 is transported away to said following unit, spray the nozzle units 28, more specifically their coolant nozzles 38, a coolant 48 on the strand surface 50 on. In this way, the strand 22 is cooled and solidifies in the strand conveying direction 26 continues. In the present case, the coolant 48 is water.
    Each of the nozzle units 28 applies a predetermined / adjustable amount of coolant to the strand surface 50. The respective amount of coolant is controlled via the control valve 40 of the respective nozzle unit 28. In the present exemplary embodiment, all the coolant nozzles 38 of a nozzle unit 28 apply the same amount of coolant to the strand surface 50.
    The temperature measuring device 44 measures a surface temperature of the strand 22 and transmits the measured surface temperature to the control unit 42. In dependence on the determined surface temperature and a predetermined surface temperature setpoint, the control unit 42 via the control valves 40, the applied from the nozzle units 28 on the strand 22 amounts of coolant in such a way that the surface temperature of the strand 22 corresponds to the predetermined surface temperature setpoint or approaches it.
    In the present case, the coolant quantities are predetermined / adjusted by the control unit 42 such that at least in a partial region of the cooling device 24, the coolant quantities in the strand conveying direction 26 alternate. In this way, 26 alternating cooling outputs are accomplished by the nozzle units 28 on an arbitrarily small surface segment of the strand 22 in the strand conveying direction.
    The quantities of coolant can, for example, over the entire length of the cooling device 24, that is across all cooling zones 30 away, alternate. Alternatively, the amounts of coolant may alternate only in one or some of the cooling zones 30.
    In the present embodiment, the quantities of coolant applied to the strand surface 50 by the nozzle units 28 arranged on the first (in the upper side) of the strand 22 alternate between a first predetermined value and a second predetermined value over the entire length of the cooling device 24 the second value is exemplarily 33% of the first value. That is, the amounts of refrigerant alternately alternate between 100% and 33% of the first refrigerant amount value at the first (top-wise) side of the strand 22 in the strand conveying direction 26.
    The quantities of coolant here alternate in the strand conveying direction 26 directly. That is, a first nozzle unit 28 applies 100% of the first coolant amount value to the strand surface 50. The next nozzle unit 28 in the strand conveying direction 26 applies 33% of the first amount of coolant to the strand surface 50. The nozzle unit 28 following this nozzle unit 28 in the strand conveying direction 26 again applies 100% of the first amount of coolant to the strand surface 50, and so on.
    In principle, the coolant quantities in the strand conveying direction 26 could alternate indirectly. For example, a first nozzle unit 28 and the nozzle unit 28 following it in the strand conveying direction 26 could apply 100% of the first amount of coolant to the strand surface 50. The next two nozzle units 28 in the strand conveying direction 26 could apply 33% of the first coolant quantity to the strand surface 50. The nozzle units 28 following the latter two nozzle units 28 in the strand conveying direction 26 could again apply 100% of the first coolant quantity value to the strand surface 50 and so on.
    The nozzle units 28 on the second (lower side of the drawing) of the strand 22 can be operated to apply the coolant 48 to the strand surface 50 according to the same pattern, that is with the same alternation, as the nozzle units 28 at the first (as shown Alternatively, the nozzle units 28 may be operated on the second (underside of the drawing) of the strand 22 to apply the coolant 48 to the strand surface 50 in accordance with a different pattern, that is, with a different alternation the nozzle units 28 on the first (in the top according to the drawing) of the strand 22.
    In addition, a vertical sectional plane II-II is shown in FIG 1, which is perpendicular to the strand conveying direction 26 in the end region of the strand guide through the continuous casting plant 2. 2 shows a schematic section through the continuous casting plant 2 from FIG. 1 along the sectional plane II-II there.
    FIG. 2 shows strand 22 and, by way of example, one of nozzle units 28. From this figure it can be seen that the illustrated nozzle unit 28 has a number of several - three exemplarily here - transverse to the strand conveying direction 26 consecutive coolant nozzles 38, wherein the strand conveying direction 26 in the illustrated nozzle unit 28 is perpendicular to the plane of FIG. The coolant 48 exits the coolant nozzles 38 in the form of cones ("coolant cones"). In the present case, the coolant cones contact the strand surface 50. In principle, it is also possible for the coolant cones to overlap.
    It can also be seen that the illustrated nozzle unit 28 has a common control valve 40 for its three coolant nozzles 38. Since in the present embodiment, the three coolant nozzles 38 are supplied via a common coolant supply line 36 with the coolant 48 and the nozzle unit 28 has a single control valve 40, the three coolant nozzles 38 are acted on the input side with the same coolant flow.
    The alternating cooling in the strand conveying direction 26, which are accomplished by the nozzle units 28 on strand 22, alternatively or additionally by alternating coolant temperatures of the applied to the arbitrarily small surface segment coolant 48, by different imparted on the arbitrarily small surface segment coolant media and / or by alternately the arbitrarily applied to the arbitrarily small surface segment coolant spray densities are effected.
    The description of the following embodiment is limited primarily to the differences from the previous embodiment, is referred to with respect to constant teristics and functions. Essentially identical or mutually corresponding elements are, as far as appropriate, designated by the same reference numerals and features not mentioned are taken over in the following exemplary embodiment, without being described again. 3 shows a further continuous casting plant 52 in a schematic representation.
    In this continuous casting plant 52, the nozzle units 28 each have an adjustable shielding unit 54 instead of a control valve. Each of the shielding units 54 is disposed between the coolant nozzles 38 of the associated nozzle unit 28 and the strand 22.
    Furthermore, the shielding units 54 each comprise two displaceable shielding plates 56 which are displaceable toward one another or away from one another along the strand conveying direction 26 with the aid of servomotors, not shown in the figures. Said actuators are controlled by the control unit 42 of the cooling device 24.
    By means of the shielding units 54, the strand surface 50 can be shielded from the coolant nozzles 38. At least a portion of the coolant 48 exiting the coolant nozzles 38 of the respective nozzle unit 28 may, depending on the position of the shielding unit 54, strike the associated shielding unit 54 instead of the strand surface 50, so that this portion of the coolant 48 will not impact the strand surface 50 meets. The shielding units 54 thus make it possible to adjust the amounts of coolant that are applied by the nozzle units 28 to the strand surface 50 in the strand conveying direction 26 alternately.
    From the shielding units 54, the coolant 48 can be guided, for example, to a coolant collecting tank, not shown in FIG.
    In principle, it is also possible that the shielding units 54 are not provided instead of control valves (cf Continuous Casting Plant 2 of FIG. 1), but in addition to control valves.
    Furthermore, in the continuous casting installation 2 of FIG. 1 and / or in the continuous casting installation 52 of FIG. 3, exit orifices may be provided in some or all of their nozzle units 28. For example, in each case a second nozzle unit 28, exit apertures can be provided in the strand conveying direction 26, while the coolant nozzles 38 of the nozzle units 28 positioned therebetween can be configured without exit apertures. Alternatively, for example, 28 exit apertures may be provided in all nozzle units. In the latter case, the exit panels can, for example, in the strand conveying direction 26 alternately differ from each other with respect to their respective opening diameter. That is, the aperture diameters of the exit apertures may alternate in the strand conveying direction 26. 4 shows an axis diagram whose abscissa axis represents values of a length coordinate x in the strand conveying direction (measured from the exit of a mold) and whose ordinate axis represents values of a strand surface temperature T.
    In the diagram, a first graph 58, a second graph 60, and a third graph 62 are shown. The graphs 58, 60, 62 each exemplify the course of a strand surface temperature T of a metallic strand in a continuous casting plant as a function of the longitudinal coordinate x when passing through a plurality of nozzle units of a cooling zone, which act on the strand surface with the same amount of coolant.
    In the first graph 58, the amount of refrigerant with which the nozzle units pressurize the strand surface is the smallest. In the second graph 60, the amount of refrigerant that the nozzle units apply to the strand surface is larger than that of the first graph 58, and in the third graph 62, the coolant amount is again larger than the second graph 60.
    All three graphs 58, 60, 62 have in common that the strand surface temperature T fluctuates between successive local minima and local maxima, while in the respective graph 58, 60, 62 the average temperature value tends towards a fixed value. A local minimum exists in each case at the position of a nozzle unit. Behind a nozzle unit increases the strand surface temperature T, due to a heat transfer from the strand interior to the cooled strand surface.
    The graph illustrates that with a variation in the amount of refrigerant that the nozzle units apply to the strand, there is a range of average strand surface temperature that can not be achieved. In the present case, the range covers temperatures of about 600 ° C to 1200 ° C.
    Based on a low amount of coolant, the cooling effect increases abruptly at a certain amount of coolant at a gradual increase in the amount of coolant. This can be attributed to the fact that at a certain amount of coolant during the passage of the strand through a coolant cone, the cooling of the strand surface is so strong that a steam film surrounding the strand surface, which stabilizes the cooling effect, can collapse. FIG. 5 shows a further axis diagram. In this diagram too, the ordinate axis represents values of a strand surface temperature T, while the abscissa axis represents values of a length coordinate x in the strand conveying direction.
    In this diagram, the same three graphs 58, 60, 62 are shown as in the diagram of FIG. In addition, a fourth graph 64 is shown in the diagram of FIG.
    The fourth graph 64 also illustrates the progression of a strand surface temperature T of a metallic strand as a function of the length coordinate x when passing through a plurality of nozzle units. The fourth graph 64, unlike the first three graphs 58, 60, 62, represents a situation in which not all the nozzle units of a cooling zone apply the same amount of coolant to the strand surface.
    Rather, for example, the first five nozzle units (counted from the mold outlet) act upon the strand surface in each case with a first predetermined amount of coolant. From the sixth nozzle unit, the even-numbered nozzle units (ie, the sixth nozzle unit, the eighth nozzle unit, the tenth nozzle unit, etc.) each apply a second coolant amount corresponding to, for example, 17% of the first coolant amount to the strand surface. The other nozzle units, however, act on the strand surface with the first amount of coolant. That is, from the sixth nozzle unit, the nozzle units act on the strand surface with coolant quantities alternating in the strand conveying direction. In this way, in the present case, a mean strand surface temperature of about 800 ° C is reached, which can not be achieved with in the strand conveying direction constant amounts of coolant.
    By selectively adjusting the coolant alternation, other temperatures in the temperature range of 600 ° C to 1200 ° C can be achieved.
    In another coolant application pattern, for example, it could be provided that the first seven nozzle units act on the strand surface with a first predetermined amount of coolant, and from the eighth nozzle unit the even-numbered nozzle units each apply to the strand surface a second coolant quantity, for example 33% of the first coolant quantity equivalent. The other nozzle units, however, can act on the strand surface again with the first amount of coolant.
    In the case of a further coolant application pattern, it could be provided, for example, that the first three nozzle units apply a first predetermined amount of coolant to the strand surface. From the fourth nozzle unit, the nozzle units with even numbering can each act on the strand surface with a second coolant quantity, which for example corresponds to 0% of the first coolant quantity. That is, it can be provided that, starting from the fourth nozzle unit, the nozzle units with even numbering do not act on the strand surface with the coolant. The other nozzle units, however, can act on the strand surface again with the first amount of coolant.
    Although the invention has been further illustrated and described in detail by the preferred embodiments, the invention is not limited by the disclosed examples and other variations can be derived therefrom without departing from the scope of the invention.
    LIST OF REFERENCES 2 Continuous casting plant 4 ladle 6 outlet tube 8 distribution basin 10 pouring tube 12 stopper 14 mold 16 mold plate 18 transport rollers 20 steel 22 strand 24 cooling device 26 strand conveying direction 28 nozzle unit 30 cooling zone 32 coolant pump 34 main coolant supply line 36 coolant supply line 38 coolant nozzle 40 control valve 42 control unit 44 temperature measuring device 46 data line 48 Coolant 50 Strand surface 52 Continuous casting plant 54 Shielding unit 56 Shielding plate 58 Graph 60 Graph 62 Graph 64 Graph
    权利要求:
    Claims (15)
    [1]
    claims
    1. A method for cooling a metallic strand (22) in a continuous casting plant (2, 52), in which by one or more coolant nozzles (38) in the strand conveying direction (26) successive nozzle units (28) accomplishes cooling performance on the strand (22) be characterized in that the cooling performance at an arbitrarily small surface segment of the strand (22) in the strand conveying direction (26) alternate.
    [2]
    2. The method according to claim 1, characterized in that in the strand conveying direction (26) alternating cooling capacities by alternating quantities of coolant, which are applied to the arbitrarily small surface segment, are effected.
    [3]
    3. The method according to claim 2, characterized in that the coolant quantities in the strand conveying direction (26) alternate directly, so that the amounts of coolant in the strand conveying direction (26) decrease or increase alternately after each nozzle unit (28).
    [4]
    4. The method according to claim 2, characterized in that the coolant quantities in the strand conveying direction (26) alternate indirectly, so that the amounts of coolant in the strand conveying direction (26) after each n nozzle units (28) alternately decrease or increase, where n is a natural number greater than 1 is.
    [5]
    5. The method according to any one of claims 2 to 4, characterized in that the amounts of coolant in the strand conveying direction (26) alternate between a first predetermined value and a second predetermined value.
    [6]
    6. The method according to any one of the preceding claims, characterized in that the nozzle units (28) each have at least one coolant nozzle (38) and the coolant nozzles (38) in the strand conveying direction (26) alternately in their respective structural design, in particular in their respective outlet diameter , different from each other.
    [7]
    7. The method according to any one of the preceding claims, characterized in that the nozzle units (28) each have at least one coolant nozzle (38) and an adjusting device (40, 54) for adjusting a coolant amount.
    [8]
    8. The method according to claim 7, characterized in that the adjusting device (40, 54) of the respective nozzle unit (28) is a control valve (40), which is arranged on the input side of the at least one coolant nozzle (38) of the respective nozzle unit (28).
    [9]
    9. The method according to claim 7, characterized in that the adjusting device (40, 54) of the respective nozzle unit (28) is an adjustable shielding unit (54) which between the strand (22) and the at least one coolant nozzle (38) of the respective nozzle unit (28) is arranged.
    [10]
    10. The method according to any one of the preceding claims, characterized in that the nozzle units (28) each have a number of transverse to the strand conveying direction (26) successive coolant nozzles (38).
    [11]
    11. The method according to any one of the preceding claims, characterized in that using a temperature measuring device (44), a surface temperature of the strand (22) is determined and the cooling performance by means of a control unit (42) in dependence on the determined surface temperature and a predetermined surface temperature setpoint be set.
    [12]
    12. The method according to any one of the preceding claims, characterized in that the nozzle units (28) elements of the same cooling zone (30) of a cooling device (24), wherein the cooling zone (30) for the nozzle units (28) has a common coolant pump (32) and / or a common coolant supply line (34).
    [13]
    13. The method according to any one of the preceding claims, characterized in that in the strand conveying direction (26) alternating cooling by alternating coolant temperatures of the applied to the arbitrarily small surface segment coolant (48), by different applied to the arbitrarily small surface segment coolant media and / or caused by alternately applied to the arbitrarily small surface segment coolant spray densities.
    [14]
    14. Cooling device (24) for cooling a metallic strand (22) in a continuous casting plant (2, 52), in particular according to a method according to one of the preceding claims, comprising a plurality of nozzle units (28) arranged successively in the strand conveying direction (26), each having one or more a plurality of coolant nozzles (38) which are adapted to perform cooling capacities on the strand (22), characterized in that the nozzle units (28) are adapted to control the cooling capacities at an arbitrarily small surface segment of the strand (22) in the strand conveying direction (26 ) to accomplish alternately.
    [15]
    15. Continuous casting plant (2, 52) with a cooling device (24) according to claim 14.
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    同族专利:
    公开号 | 公开日
    AT518450B1|2021-02-15|
    DE102017105614A1|2017-09-21|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    WO2002034432A1|2000-10-20|2002-05-02|Sms Demag Aktiengesellschaft|Method and device for continuous casting and subsequent forming of a steel billet, especially a billet in the form of an ingot or a preliminary section|
    WO2004048016A2|2002-11-23|2004-06-10|Sms Demag Aktiengesellschaft|Method and device for continuously casting slab bars, thin slab bars, blooms, pre-profiled billets, billets, and similar made of liquid metal, particularly steel material|
    EP1550523A1|2004-01-03|2005-07-06|SMS Demag AG|Diversified regulation of the secondary cooling of a continuous casting machine|
    WO2016012471A1|2014-07-25|2016-01-28|Primetals Technologies Austria GmbH|Cooling of a metal strand portion|
    JPS63112058A|1986-10-28|1988-05-17|Mitsubishi Heavy Ind Ltd|Continuous casting method|CN109877288B|2019-04-01|2021-03-16|包头钢铁（集团）有限责任公司|Control process method for central equiaxial crystal rate of oriented silicon steel casting blank|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    ATA50223/2016A|AT518450B1|2016-03-17|2016-03-17|Method and cooling device for cooling a metallic strand|ATA50223/2016A| AT518450B1|2016-03-17|2016-03-17|Method and cooling device for cooling a metallic strand|
    DE102017105614.9A| DE102017105614A1|2016-03-17|2017-03-16|Method and cooling device for cooling a metallic strand|
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