Method and apparatus for non-contact determination of at least one property of at least partially molten continuously cast strand

Abstract

The invention relates to a method for contactless determination of at least one property of an at least partially molten continuously cast strand during a casting process of the continuously cast strand, which is cooled in a cooling zone in such a way that a gradual hardening of the continuously cast strand can be achieved, the method comprising at least the following steps: emitting a first signal, in particular a first radar signal, in the form of radiation by an emitting device, in particular a radar emitting device, generating a second signal, in particular a second radar signal, at least partially by interaction of the first signal with a region of the continuously cast strand, receiving the second signal by a receiving device, in particular by a receiving device for radar signals, determining at least one property of the continuously cast strand on the basis of the second signal, wherein at least the step of interaction is carried out in the cooling zone or upstream of the cooling zone (K), in particular immediately after the mold exit. The invention also relates to a device for casting material, in particular metal, to form a continuously cast strand and for contactless determination of at least one property of an at least partially molten continuously cast strand during casting of the continuously cast strand in the field of continuous casting methods, the device comprising: a mold, which is suitable for shaping the continuously cast strand; a cooling zone, in which the continuously cast strand is cooled in such a way that a gradual hardening of the continuously cast strand can be achieved; an emitting device, in particular a radar emitter, which is set up to emit a first signal in the form of radiation, in particular as a first radar signal; a receiving device, in particular a radar receiver, which is set up to receive a second signal, in particular a second radar signal, wherein the second signal is generated at least partially by interaction of the first signal with a region of the continuously cast strand in the cooling zone or upstream of the cooling zone, in particular immediately after the mold exit; a data processing unit, which is set up to determine at least one property of the continuously cast strand on the basis of the second signal. According to the invention, a corresponding use is also described.

Description

Technical Field

[0001] The invention relates to a method for contactlessly determining at least one property of an at least partially molten quasi-endlos strand during the casting process of the quasi-endlos strand, which is cooled in a cooling zone. Background Art

[0002] Casting of metals and alloys is a manufacturing process in which individually shaped workpieces (castings) are made from liquid metal (molten metal, such as steel). There are many different casting processes, which can be classified according to several criteria.

[0003] The most common method of die casting is casting in a mold that closely matches the shape of the finished part. In addition, there is also the casting of continuous strands, which is theoretically continuous casting.

[0004] Continuous casting is a continuous process for the discontinuous and continuous production of cast products (such as (rolled) billets and compacts, also called billets) made of ferroalloys and non-ferrous alloys. In steel mills, they are also called (rolled) slabs.

[0005] Continuous casting techniques differ slightly whether processing steel, copper alloys or aluminum. The main difference lies in the temperature, which ranges from approximately 700°C for pure aluminum or aluminum alloys to 1,400°C or 1,550°C for steel.

[0006] Depending on the mould arrangement, a distinction is made between horizontal and vertical continuous casting, with the former being used exclusively for copper alloys and small-sized billets.

[0007] In the field of vertical systems, those skilled in the art are familiar with vertical, vertically curved, and curved systems (particularly progressive and circular bends). In these cases, after leaving the mold, the billet is guided in a cooling zone (K) by supporting billet guides (e.g., support roller stands), which can be arranged vertically or on the bend. In this area, particularly in vertically curved and curved systems (also referred to as the bending zone), the core of the strand remains liquid and hardens as it advances through the cooling zone (K). In vertically curved and curved systems, the strand is straightened by a straightener after reaching horizontality.

[0008] In continuous casting plants, during the production process, the temperature of the cast strand obtained at each cross-sectional position during solidification decreases from the casting temperature of about 1,550°C depending on the analysis to less than 900°C, sometimes less than 700°C. The ductility of the steel used represents an evaluation criterion of the weakening of the material, which has a local minimum in this temperature interval. Therefore, when carrying out the casting process, the temperature is controlled to a specific value, which is selected and adjusted in such a way that the ductility of the crack critical bending and straightening areas of the casting plant during the production of the cast strand is sufficiently high to avoid cracks.

[0009] In the continuous casting process of slabs (rolled steel slabs and compacted slabs), liquid steel is poured into a water-cooled copper mould with a bottom opening. The steel material leaves this opening in solidified form in the outer region and is continuously drawn off as a continuous cast strand by guide and drive rolls. The cast strand is also cooled internally during the process from a vertical position to a horizontal position of more than 15 meters deep. For this purpose, water is constantly sprayed, which has a relatively tough and strong structure due to the rapid cooling.

[0010] The continuous casting products are also called semi-finished products, since they have to go through further processing steps before they become final products. Primarily rolling, pressing and deep drawing are used, combined with a prior ageing at room or ambient temperature for a certain time, or a prior or subsequent heat treatment (annealing and ageing).

[0011] Various methods for determining properties, in particular disturbances in the casting process, are known from the prior art.

[0012] In particular, radiation measurement systems, ultrasonic measurement systems, radar measurement systems, optical measurement systems (laser, camera) and / or force measurement systems are used for determining properties. In certain steel industry cases, X-rays or isotope solutions are used for precise measurements. However, these technologies emit radiation and are expensive to maintain.

[0013] The disadvantage of ultrasonic measurement systems and optical measurement systems is that the difficult conditions of the steel industry, such as heat radiation, cooling evaporated water and dust, hinder the use of sensors for measurements at many positions which are advantageous for obtaining geometric information about the quality of the production. A comparison of sensor technologies shows that ultrasonic or optical sensors (laser, camera) are negatively affected by the medium in the atmosphere of the steel plant. Therefore, none of the above-mentioned measurement systems can cope with all these disturbance factors at the same time and at the same time reproduce the high precision values of the laboratory situation in this case.

[0014] Radar can measure all these areas. Although at first glance radar technology can not be as accurate as laser in the laboratory situation, radar still maintains its precision in the real atmosphere of the steel plant. Radar sensors usually emit electromagnetic waves based on technology similar to a cell phone. The radiation is many times, preferably 1000 times, lower than that of an ordinary cell phone.

[0015] The positioning of the measuring device presents a particular challenge for this measuring arrangement. The high temperature of the strand before it passes through the cooling zone makes measurement in this area more difficult and subjects the measuring device to negative influences, particularly high temperatures and heat radiation, which can impair its function.

[0016] For example, DE 10 2018 108 696 A1 describes an optical measuring method for contactless determination of the dimensions of a moving material web.

[0017] WO 96 / 36449 discloses a method for continuously casting steel in a mold. Here, liquefied steel and synthetic slag are fed into the mold via a pipe extending through an insulating cover. Using radar or other radiation-based measuring devices, the flow of liquefied steel and synthetic slag is controlled so that the material surface continuously maintains a constant, predetermined distance from the cover. This method relies on a defined position of the liquefied steel and slag relative to the insulating cover. No material properties, such as density, width, temperature, or homogeneity, are measured.

[0018] EP 3628416 A1 discloses a method and a device for continuously casting metal products, comprising a mold, a strand-supporting guide connected to the mold, along which the strand emerging from the mold, in particular vertically downward, can be transported in a conveying direction. It is crucial that the strand has completely hardened or solidified within the strand-supporting guide (i.e., within the cooling zone) to prevent the liquid metal core from fracturing. The strand thickness is measured by a radar measuring device at a measuring position directly at the end of the strand-supporting guide (i.e., downstream of the cooling zone). A control signal is generated by a calculation unit, signal-relatedly connected to the radar measuring device, by comparison with a predetermined strand thickness. This control signal is used to adjust at least one casting parameter based on the measured deviation.

[0019] However, this method has the disadvantage that the strand has already completely passed through the strand support guide during measurement. If the strand thickness changes in this area, this can affect the strand support guide and, due to the increased loads in the straightening system area, lead to increased wear on the support rollers, especially in arched installations.

[0020] In EP 3628416 A1, only the thickness of the strand is considered a measured variable. No statements can be made about the quality of the casting process with respect to properties such as width, density, temperature, and uniformity. If defects are detected in the strand at this stage or later in the process, this can lead to increased scrap rates. Summary of the Invention

[0021] The technical object of the present invention is therefore to provide a method for reliably detecting faults or defects during a casting operation, in particular after leaving the mold, which method is particularly precise, resource-saving and enables extensive possibilities for continuous error correction.

[0022] Furthermore, the object of the invention is to avoid the use of additional sensors as much as possible in order to keep maintenance and repair costs as low as possible.

[0023] The continuous cast strand may be, for example, a metal web, for example in the form of a metal foil, a paper web, a plastic web, an opaque textile web, a composite material web or a multilayer material web.

[0024] The material web is preferably flat with respect to its length and width and has a large length compared to its width.The dimension of the material web to be determined is then preferably the width.

[0025] Preferably, the at least partially molten continuous strand is a partially molten continuous metal strand (ie a metal web).

[0026] A quasi-continuous strand or quasi-continuous strand is a long continuous strand. In fact, a quasi-continuous strand can definitely have an end, so the quasi-continuous strand is only quasi-continuous. This only means that the method has the property of allowing, for example, continuous operation and continuous strand production. The quasi-continuous strand can actually be limited at a certain place or at a certain moment. In one example, the mold used to produce the quasi-continuous strand is empty at a certain point in time. As the method continues to be executed, the quasi-continuous strand will now end unless the mold is continuously filled with material, i.e. refilled, in order to provide more raw material for the continuous continuation of strand production.

[0027] An example of continuous metal casting is slab production, particularly in a continuous casting process.

[0028] Depending on the shape of the mold, other cross-sections can also be produced. On the other hand, in the case of square or round cross-sections, we no longer speak of slabs but rather so-called billets, wherein in the continuous casting plant, the liquid metal as a slab is discharged vertically downward from the mold (K) in the conveying direction, guided along the billet guide (S), and turned horizontally.

[0029] Cooling in the mold is called "primary cooling." As the steel cools and solidifies in the mold, only a thin strand shell forms. In particular, this thin strand shell forms only directly after the liquid metal leaves the mold. After this thin strand shell has formed, the strand leaves the mold and is cooled by supporting strand guides in a cooling zone (K) (also called a secondary cooling zone) adjacent to the mold until it is completely hardened (see the German Ironworks Association (VEDh), Steel Fiber, Steel Publishing House, Düsseldorf, 2002).

[0030] There are vertical and horizontal continuous casting processes. In vertical processes, there are usually different zones (bending zone, rounding zone, straightening zone) in which the vertical strand passes through a curve in order to also transform into a horizontal strand at the end of the process.

[0031] In the first cooling zone, the slab is usually intensively cooled so that a microstructural transformation from austenite to ferrite occurs in the near-surface edge region of the slab.

[0032] A basic idea of ​​the invention is to determine the strip edge position or the bandwidth of the metal strip using two or more radar sensors, preferably high-frequency sensors of the FMCW (Frequency Modulated Continuous Wave) type in the range of 30 to 300 GHz.

[0033] Discussion of the invention and possible implementations

[0034] The present invention belongs to the field of radar (RADAR) technology. Radar means "radio detection and ranging". Roughly translated, it roughly means "radio-aided positioning and distance measurement".

[0035] The invention can be used particularly advantageously in conjunction with the field of casting technology.

[0036] Although the established wording implies a restriction to radio frequencies, this is not absolutely necessary for the invention, and electromagnetic waves of all other frequencies (including light) or other physical wave phenomena, such as sound and ultrasound, may also be used.

[0037] In the previous section, relevant problems of the existing technology in the field of radar technology were described.

[0038] According to the invention, the problem of the prior art is solved by a method according to claim 1. Preferred embodiments and developments are defined in the dependent claims.

[0039] Therefore, a method is provided for contactlessly determining at least one property of an at least partially melted quasi-continuous ingot during a casting process of the quasi-continuous ingot, wherein the quasi-continuous ingot is cooled in a cooling zone (K), in which case gradual hardening of the quasi-continuous ingot can be achieved, the method comprising at least the following steps: transmitting a first signal, in particular a first radar signal, in the form of radiation by a transmitting device, in particular a radar transmitting device, generating a second signal, in particular a second radar signal at least partially by interaction (S02b) of the first signal with an area of ​​the quasi-continuous ingot, receiving the second signal by a receiving device, in particular a receiving device for radar signals, and determining at least one property of the quasi-continuous ingot based on the second signal, characterized in that at least the step of interaction is carried out in the cooling zone or upstream of the cooling zone (K), in particular immediately after the mold outlet.

[0040] The invention also provides an apparatus according to claim 18. Thus, an apparatus is provided for casting a material, in particular a metal, into a quasi-continuous strand in the context of a continuous casting method and for contactlessly determining at least one property of the at least partially molten quasi-continuous strand during casting of the quasi-continuous strand, the apparatus comprising: a mold suitable for shaping the quasi-continuous strand; a cooling zone in which the quasi-continuous strand is cooled such that a gradual hardening of the quasi-continuous strand is achieved; a transmitting device, in particular a radar transmitter, which is configured to transmit a first signal in the form of radiation, in particular as a first radar signal; a receiving device, in particular a radar receiver, very particularly preferably a radar sensor, which is configured to receive a second signal, in particular a second radar signal, wherein the second signal is generated at least in part by the interaction of the first signal with a region of the quasi-continuous strand in the cooling zone or upstream of the cooling zone, in particular immediately after the mold outlet; and a data processing unit, which is configured to determine at least one property of the quasi-continuous strand based on the second signal.

[0041] For example, the transmitting device and the receiving device are designed as sensors. For example, it may be advantageous if the radar sensor and the radar receiver are designed as a single radar sensor (also called a radar transceiver).

[0042] The invention also provides for the use of a transmitting device and a receiving device as claimed in claim 19. Thus, in particular, the use of a transmitting device and a receiving device for radar signals for contactlessly determining at least one property of an at least partially melted quasi-continuously cast strand during the casting process of the quasi-continuously cast strand, the quasi-continuously cast strand being cooled in a cooling zone, in which case a gradual hardening of the quasi-continuously cast strand can be achieved, wherein the transmitting device and the receiving device are arranged such that they determine at least one property of the quasi-continuously cast strand in the cooling zone or upstream of the cooling zone (K), in particular immediately after the mold exit.

[0043] Preferred embodiments and developments of the main claims can also be combined individually or in combination with the corresponding clauses.

[0044] The present invention has the particular advantage that the measurement is already performed in the cooling zone or upstream of the cooling zone (K), in particular, immediately after exiting the mold. Because the interacting steps occur upstream of the cooling zone or cooling zone (K), in particular immediately after exiting the mold, at least one property of the quasi-continuously cast strand in the cooling zone or upstream of the cooling zone, in particular, immediately after exiting the mold, is considered. Information about the quasi-continuously cast strand in the cooling zone is particularly valuable because the continuous casting process has not yet progressed very far at the time of measurement. Therefore, the measurement is performed very early in the ongoing continuous casting process.

[0045] This can save material. For example, a defective process can be detected early and aborted, saving resources. In another example, defects detected in this way can be effectively corrected because the defective material of the quasi-continuously cast strand has not yet been converted into a fully cooled, solid aggregate. This offers the potential for advantageous corrections and further processing, for example, because the material can be better formed and any parameters of the cooling process can still be adapted.

[0046] Measurements in the cooling zone or upstream of the cooling zone (K), especially immediately after exiting the mold, are often more difficult to perform or may be less accurate because the physical environment in the cooling zone or upstream of the cooling zone (K), especially immediately after the mold exit, can interact with or interfere with the measurement process. In particular, measurements using electromagnetic waves in the radio spectrum or in areas adjacent to this spectrum have proven to be particularly robust and therefore offer a particularly robust and reliable method. Although radar technology may appear to be less accurate than laboratory lasers in laboratory conditions at first glance, radar maintains its accuracy in the real atmosphere of a steel mill, especially when measuring directly on the strand in the cooling zone or upstream of the cooling zone (K), especially in the area immediately after the mold exit, or when the measuring device is arranged in the cooling zone or upstream of the cooling zone (K), especially immediately after the mold exit, where the strand still has a very high temperature.

[0047] As also recognized by those skilled in the art in the field of control technology, there are numerous possibilities for combining the invention with suitable control circuits.

[0048] Preferred embodiments

[0049] According to a further embodiment, the method further comprises the step of processing defects or anomalies in the quasi-continuously cast strand, said defects or anomalies being determined based on the determined properties or secondary variables determined thereby, in particular by terminating the casting process or generating logs or instructions which are suitable for subsequently removing defect-affected areas of the quasi-continuously cast strand during further processing, in particular also by cutting off defect-affected areas during continuous cutting of the quasi-continuously cast strand into slabs.

[0050] According to a further embodiment, at least one specific property of the quasi-continuously cast strand is selected from the group consisting of distance, width, thickness, density, temperature, and uniformity. Thus, various technically relevant properties can be efficiently determined at an early stage. In particular, distance can be measured. For example, a specific distance can be used to maintain a target distance or as an input for calculating other dimensions, such as the width of the quasi-continuously cast strand.

[0051] According to a further embodiment, uniformity is determined as a property of the quasi-continuous ingot. In particular, uniformity can be determined by determining the surface quality or surface structuring of the quasi-continuous ingot. During the casting process, the mold vibrates in the vertical direction. This is necessary so that the ingot shell formed does not stick to the mold wall. However, due to the vibration of the mold in the vertical direction during the casting process, changes in the (sub) millimeter range are formed on the surface of the quasi-continuous ingot, in particular on its narrow sides. Those skilled in the art refer to the gaps thus generated as oscillation marks. In a particularly preferred embodiment, the present invention is determined by performing a roughness measurement on the surface roughness of the quasi-continuous ingot, and thus statements about the oscillation marks can be made, which allow conclusions to be drawn about the uniformity and the quality of the casting process. In a particularly preferred embodiment, the determination of the surface roughness is achieved by a non-contact method. Measurement methods based on electromagnetic waves, such as radio frequency, ultrasound, infrared or optical wavelengths, but in particular in the radio frequency range (radar technology), such as using radar signals, are particularly preferred. In the preferred method, the oscillation mark is determined by forming a difference between two distances in the (sub) millimeter range. For example, the depth t of the oscillating mark is determined as t=x1-x2, where x1 and x2 represent determined distances.

[0052] According to a further embodiment of the invention, the method for contactlessly determining at least one property of an at least partially melted quasi-continuously cast ingot and the device for casting material defined herein are both used to determine oscillation marks of the quasi-continuously cast ingot, in particular on its surface, preferably in the cooling zone or in an area upstream of the cooling zone (K), in particular immediately after coming out of the mold.

[0053] According to another variant, steps S01 to S03 are carried out from two different positions, in particular from two essentially oppositely arranged positions with respect to the quasi-continuously cast strand.

[0054] According to another embodiment, the width of the quasi-continuous billet is determined by forming the difference between the sum of two specific distances and the distances between two different positions, or the width of the quasi-continuous billet is determined by subtracting the two specific distances from the distances between two different positions, in particular when the emission and reception are essentially at right angles to the surface of the quasi-continuous billet.

[0055] This allows the width of the strand to be efficiently determined and monitored, allowing corrective measures to be taken. For example, the width b can be determined as b = d - x1 - x2, where x1 and x2 represent two defined distances and d represents the distance between two different positions. For example, b = d - (x1 + x2) can also be calculated.

[0056] This calculation has a favorable behavior in terms of error propagation.

[0057] According to a further embodiment, the width of the quasi-continuous strand is determined by forming the difference between the sum of two specific distances and the distances of two different positions from one another, or by subtracting the two specific distances from the distances of two different positions from one another, wherein the emission and reception take place essentially at right angles to the surface of the quasi-continuous strand, and wherein, when determining at least one of the two distances, trigonometric functions are also used to correct for the effects of angular deviations from the perpendicular measurement. This makes the calculation more accurate.

[0058] In one example, the distance traveled or the time traveled is multiplied by the cosine of the angle. For example, this is the angle of incidence or the deviation of the angle of incidence from a right angle. It can also be half the angle between the incoming and outgoing signals.

[0059] In particular, by correctly accounting for angles, angular measurements become more accurate. This leads to more precise calculations. For example, the effective average total distance of the transmitting and receiving devices from the strand can be determined more precisely in this way, allowing the strand width to be calculated more accurately over time.

[0060] According to a further embodiment, a wall (51, 52, 61, 62) is arranged between the transmitting device and the quasi-continuously cast strand, wherein the wall (51, 52, 61, 62) has a pore (7) through which the signal propagates. Such a wall (51, 52, 61, 62) provides protection, for example, from temperature influences. The pore enables measurement. Due to the pore, the measurement is particularly focused.

[0061] According to a further embodiment, the aperture is dimensioned so as to create an effective aperture angle for the transmitting device that is at most 80% of the transmitting device's transmission angle. Thus, the aperture creates an effective aperture angle that is significantly smaller than the transmitting device's transmission angle. This allows for better focusing and thus very precise measurements.

[0062] According to a further solution, the distance between the emitting device and the wall (51, 52, 61, 62) is at least 10 cm. This can prevent the influence of temperature and is very easy to maintain and clean.

[0063] According to a further embodiment, the quasi-continuous strand is produced in a continuous casting method. In such a continuous casting method, expensive raw materials are processed at high temperatures with the highest energy consumption.

[0064] Therefore, the cost savings achieved by using the present invention are particularly high when it is used in a continuous casting process. Consequently, errors can be detected early and corrected if necessary. This effectively saves material, energy, labor, and other resources.

[0065] According to a further embodiment, the transmitting device and / or the receiving device are arranged in the cooling zone or upstream of the cooling zone (K), in particular immediately after the mold exit. Since, according to the invention, the measurement is performed on the strand in the cooling zone or upstream of the cooling zone (K), in particular immediately after it has emerged from the mold, the arrangement of the transmitting device and / or the receiving device in the cooling zone or upstream of the cooling zone (K), in particular immediately after the mold exit, allows for an efficient device design and short signal path lengths. This allows for very precise operation of the device.

[0066] According to a further embodiment, the transmitting and receiving devices include shared equipment, in particular a common radar transceiver. This saves costs, as only one device is required. Furthermore, measuring at right angles to the ingot is particularly easy. In many radar setups, only a single calibration is required.

[0067] According to a further embodiment, a mold is used in the continuous casting method, by means of which the quasi-continuously cast strand is formed, wherein steps S01 to S03 are performed immediately after the mold.

[0068] According to a further embodiment, the transmitting device and / or the receiving device is protected by a diaphragm consisting of PTFE which is stable at least up to 260° C. and / or a ceramic which is stable at least up to 1,400° C.

[0069] Partitions effectively protect the corresponding equipment from temperature and other environmental influences.

[0070] According to a further embodiment, the transmitting and / or receiving device is protected by a first partition, which is in particular designed as a perforated partition, and the holes are covered by a second partition, wherein the second partition is formed from PTFE. This combines good protection with good transmitting and receiving properties of the corresponding device.

[0071] According to a further embodiment, the transmitting device and / or the receiving device comprises a lens structure, which is used, for example, to focus the electromagnetic waves, thereby facilitating precise measurements.

[0072] According to a further embodiment, the transmitting device and / or the receiving device comprises a horn antenna and / or a phased array antenna. Horn antennas and phased array antennas have radiation properties that are particularly suitable for use in conjunction with the present invention. In general, various directional radio antennas can be used in conjunction with the present invention.

[0073] According to a further aspect, the present invention operates in continuous wave mode, in particular frequency modulation, and in particular as a continuous wave radar. This is particularly well suited for the intended purpose and is particularly accurate. It also enables continuous monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] The invention is explained in more detail below with reference to exemplary embodiments presented in the schematic drawings of the accompanying drawings, in which:

[0075] Figure 1 A device for carrying out a continuous casting method (continuous casting facility) is shown;

[0076] Figure 2 A device for carrying out a continuous casting method (continuous casting installation) is shown, which is configured for the method according to the invention according to one embodiment, and is particularly configured for determining the thickness of a quasi-continuously cast strand;

[0077] Figure 3 A device for carrying out a continuous casting method (continuous casting installation) is shown, which is configured for the method according to the invention according to one embodiment, and is particularly configured for determining the thickness of a quasi-continuously cast strand;

[0078] Figure 4 A device for carrying out a continuous casting method (continuous casting installation) is shown, which is configured for the method according to the invention according to one embodiment, and is particularly configured for determining the thickness of a quasi-continuously cast strand;

[0079] Figure 5 The simplified schematic diagram of a device for carrying out a continuous casting method (continuous casting installation) is shown, which is provided for the method according to the invention according to one embodiment and is provided in particular for determining the width of a quasi-continuously cast strand. DETAILED DESCRIPTION

[0080] Continuous casting facilities are usually Figure 1 The continuous casting facility operates as shown. A bottom-open casting mold 4 is filled with molten steel 2 or molten metal 2. Primary cooling occurs in the mold 4. The still-liquid molten metal flows into a channel (also called the die) at approximately 1,600°C, where it cools. Heat is dissipated through the mold walls, causing the metal to solidify and form a load-bearing outer shell. This means that a hard shell forms on the outside during cooling. The solidification temperature depends on the composition; for example, for steel, it is approximately 1,150°C to 1,500°C. This so-called strand shell contains a liquid core. The solidified strand shell is continuously pulled out of the mold and carried further, supported by rollers 5. In the primary cooling station, approximately 12% of the metal's energy is typically removed by water cooling in the mold. The mold walls typically consist of coated or uncoated copper plates. The back of the copper plates is cooled by contact with cooling water. The cooling water is pumped through cooling channels or cooling gaps provided for this purpose between the mold walls and the support plates. The cooling water flow rate is high and selected to achieve a temperature increase of 6 to 15°C. The mold heat dissipation is high, at approximately 2 megawatts per square meter. Unused energy is dissipated via heat exchangers and cannot be recovered in this form. At the first stage, after the mold, secondary cooling occurs via spray cooling with water or an air-water mixture. This secondary cooling uses spray water cooling, radiation, and closed-circuit cooling to remove heat from the strand until solidification or a stable shell is reached, eliminating the need for further cooling. The solidified metal strand is then cut into blocks—slabs, blooms, billets, or ingots—and further processed or temporarily stored. The energy content of these blocks or ingots still corresponds to approximately 50% of that of the liquid metal.

[0081] Figure 1-5 The continuous casting facilities are shown and described together as much as possible below. Figure 2-5 The device in is configured to enable the present invention to be used. Figure 2 、 3 The apparatus in and 4 is particularly configured such that the present invention can be used to determine the thickness of a quasi-continuously cast strand. Figure 5 The device in the embodiment is particularly configured such that the invention can be used to determine the width of a quasi-continuously cast strand. For many processes, the determination of the width is particularly relevant.

[0082] The ladle 1 contains a liquid metal melt 2 , which flows from the ladle into a distributor 3 and from there into a mold 4 through a pouring tube 10 , thereby forming a quasi-continuously cast strand 100 .

[0083] All figures show a vertical casting process, but the invention can also be used for other casting processes, such as horizontal casting processes.

[0084] For example, the strand is produced and continuously cooled as described above. The strand is guided here by the drum / roller 5 and the cooling device 6 and cooled successively.

[0085] The completed continuous casting strand 100 b is divided into, for example, slabs 9 or billets by a cutting device 8 , such as one or more cutting torches or one or more plasma torches 8 .

[0086] exist Figure 2 In particular, a radar transmitting device 11, a radar receiving device 12 and a radar transceiver 13 are shown, which are configured for the method according to the invention.

[0087] In this example, a radar transmitting device 11 and a separate radar receiving device 12 are used on the left. In this example, a radar transceiver 13 is used on the right. However, this arrangement is only an example. As to whether a transceiver or a separate transmitting device and receiving device is to be used, a choice can be made independently of each other not only on the left but also on the right. All combination choices (1. Left: transceiver, right: transceiver; 2. Left: transceiver, right: transmitter + receiver; 3. Left: transmitter + receiver, right: transceiver; 1. Left: transmitter + receiver, right: transmitter + receiver) are compatible with the present invention. For example, Figure 3 Two radar transceivers 31 and 32 are shown in FIG.

[0088] Further, i.e. additional, measurements can also be performed on horizontal strands. Figure 2 Figure 2 shows a radar transmitter 21, a radar receiver 22, and a radar transceiver 23. This additional measurement offers numerous advantages. For example, it is possible to check on the horizontal strand whether defects detected during the first measurement on the vertical strand can be eliminated. Furthermore, the material has cooled further, so the measurement here provides values ​​that are closer to those of the finished product.

[0089] However, Figure 2This arrangement of the radar transmitting device 21, the radar receiving device 22 and the radar transceiver 23 in the embodiment is also merely an example. Whether a transceiver or a separate transmitting device and receiving device is to be used can be selected independently of each other not only on the upper side but also on the lower side. All combination options (1. upper: transceiver, lower: transceiver; 2. upper: transceiver, lower: transmitter + receiver; 3. upper: transmitter + receiver, lower: transceiver; 1. upper: transmitter + receiver, lower: transmitter + receiver) are possible here and are also compatible with the combination according to the teaching of the invention. For example, Figure 3 Two radar transmitting devices 36 and 38 and two radar receiving devices 37 and 39 are shown.

[0090] In all figures, the positioning of the associated transmitting and receiving devices is merely exemplary. Figure 2 The radar transmitting device 11 in the figure can also be located at the position shown by the radar receiving device 12, and the radar receiving device 12 is located at the position shown by the radar transmitting device 11.

[0091] Figure 3 Also disclosed are walls or covers 51, 52, 61, 62 having apertures through which signal transmission can take place. The apertures can also be filled with a suitable material. The advantages of the walls or covers are apparent from the description of the invention and its developments.

[0092] Figure 5 The apparatus is particularly configured so that the invention can be used to determine the width of a quasi-continuously cast strand. Figure 5 This is particularly reflected in the position and orientation of the radar transmitting device 11, the radar receiving device 12 and the radar transceiver 13 (and possibly the walls 51, 52). The orientation of the radar signals 101, 102, 103 is also adjusted accordingly. Figure 5 These fall on one side of the quasi-continuous strand 100 or emanate from it.

[0093] Also in Figure 5 The positioning of the associated transmitting and receiving devices is merely exemplary. Figure 5 The radar transmitting device 11 in the figure can also be located at the position shown by the radar receiving device 12, and the radar receiving device 12 is located at the position shown by the radar transmitting device 11.

[0094] exist Figure 5In this example, a radar transmitting device 11 and a separate radar receiving device 12 are used on the left. In this example, a radar transceiver 13 is used on the right. However, this arrangement is only an example. As to whether a transceiver or a separate transmitting device and receiving device is to be used, the choice can be made independently of each other not only on the left but also on the right. All combination choices (1. Left: transceiver, right: transceiver; 2. Left: transceiver, right: transmitter + receiver; 3. Left: transmitter + receiver, right: transceiver; 1. Left: transmitter + receiver, right: transmitter + receiver) are compatible with the present invention. A person skilled in the art recognizes that the terms "left" and "right" referring to the corresponding figures are not used in the same way. Figure 5 In the context of Figure 1-4 The definition is different in the context of .

[0095] For many processes, the determination of width is particularly relevant. For clarity, Figure 5 Shown in simplified form.

[0096] Reference Signs List

[0097] 1 Ladle

[0098] 2 Melt

[0099] 3 Allocators

[0100] 4 Mold

[0101] 5 rollers

[0102] 6 Cooling equipment

[0103] 7 Porosity

[0104] 8 Cutting equipment

[0105] 9 slab

[0106] 10 pouring tube

[0107] 11 Radar transmitting equipment

[0108] 12 Radar receiving equipment

[0109] 13 radar transceiver

[0110] 21 Radar transmitting equipment

[0111] 22 Radar receiving equipment

[0112] 23 radar transceiver

[0113] 31 radar transceiver

[0114] 32 radar transceivers

[0115] 36 Radar transmitting equipment

[0116] 37 Radar receiving equipment

[0117] 38 radar transmitting equipment

[0118] 39 Radar receiving equipment

[0119] 51 wall / protective cover

[0120] 52 wall / protective cover

[0121] 61 wall / protective cover

[0122] 62 wall / protective cover

[0123] 100, 100b semi-continuous casting

[0124] 101 Second radar signal (secondary signal)

[0125] 102 First radar signal (main signal)

[0126] 103 The first radar signal (primary signal) and the second radar signal (secondary signal) overlap in space

[0127] Further disclosure

[0128] The invention particularly comprises a method as defined herein, wherein a mold is used in a continuous casting method, by which a quasi-continuous strand is formed, wherein steps S01 to S03 are performed immediately downstream of the mold, ie upstream of the cooling zone (K).

[0129] For example, a method can be provided in which the transmitting device and / or the receiving device is protected by a diaphragm consisting of PTFE which is stable at least up to 260° C. and / or a ceramic which is stable at least up to 1,400° C.

[0130] In one embodiment of the method, provision can be made for the transmitting device and / or the receiving device to be protected by a first separator, which is in particular designed as a perforated plate, and for the perforations to be covered by a second separator, wherein the second separator is formed from PTFE.

[0131] The advantage of the partition, in particular the orifice plate protection, is the improved quality and thus the high precision of the measuring device. Furthermore, no additional partitions (e.g., walls or protective covers) are required, as in the case of open or at least semi-open measuring arrangements, so that the transmitting and / or receiving devices can be positioned directly in the cooling zone. Even at the highest temperatures (as defined herein) that can occur during continuous casting, the properties of the quasi-continuously cast strand (100, 100b) can still be determined very well.

[0132] In one embodiment of the method, it may be provided that the transmitting device and / or the receiving device comprises a lens structure. Based on the corresponding lens structure, it is possible to compensate for possible deviations (i.e., aberrations or image defects) that may occur during the determination of at least one property of the quasi-continuously cast strand (100, 100b), for example due to the high temperatures (as defined herein) occurring during the continuous casting process.

Claims

1. A method for contactlessly determining at least one property of an at least partially molten quasi-continuously cast strand (100, 100b) during a casting process of the quasi-continuously cast strand (100, 100b), the quasi-continuously cast strand being cooled in a cooling zone (K) such that a gradual hardening of the quasi-continuously cast strand (100, 100b) is achieved, the method comprising at least the following steps: - transmitting (S01) a first radar signal (102) in the form of radiation by means of a transmitting device (11, 13, 31, 32), - generating (S02a) a second radar signal (101) at least partially by interaction (S02b) of the first radar signal (102) with a region of the quasi-continuously cast strand (100, 100b), - receiving (S03) the second radar signal (101) by a receiving device (12, 13, 31, 32), - determining (S04) at least one property of the quasi-continuously cast strand (100, 100b) based on the second radar signal (101), characterised in that at least the step of interaction (S02b) is carried out in the cooling zone (K) or upstream of the cooling zone (K), At least one property of the quasi-continuously cast strand is selected from the group consisting of distance, width, thickness, density, temperature and uniformity, A wall (51, 52, 61, 62) is arranged between the transmitting device and the quasi-continuously cast strand, wherein the wall has pores (7) through which signal propagation is possible.

2. The method according to claim 1, wherein The method further comprises: - A step of processing (S05) defects or anomalies in the quasi-continuously cast strand (1), said defects or anomalies being determined based on the determined properties or secondary variables determined thereby.

3. The method according to claim 2, wherein: Defects or anomalies in the quasi-continuously cast strand (1) are handled (S05) by suspending the casting process or generating logs or instructions suitable for subsequently removing the area of ​​the quasi-continuously cast strand (9) affected by the defect during further processing.

4. The method according to claim 3, wherein: By cutting away the areas affected by defects during continuous cutting of the quasi-continuously cast strand into slabs.

5. The method according to any one of claims 1 to 4, wherein Steps S01 to S03 are performed from two different locations.

6. The method according to claim 5, wherein: Steps S01 to S03 are performed from two substantially oppositely arranged positions with respect to the quasi-continuously cast strand.

7. The method according to claim 5, wherein: When emission (S01) and reception (S02) are performed essentially at right angles to the surface of the quasi-continuous ingot, the width of the quasi-continuous ingot is determined, according to step S04, by forming the difference between the sum of two specific distances and the distances between two different positions, or wherein, according to step S04, the width of the quasi-continuous ingot is determined by subtracting the two specific distances from the distances between two different positions.

8. The method according to claim 7, wherein: According to step S04, the width of the quasi-continuous ingot is determined by forming the difference between the sum of two specific distances and the distances between two different positions from each other, or, according to step S04a, the width of the quasi-continuous ingot is determined by subtracting the two specific distances from the distances between two different positions from each other, wherein the emission (S01) and the reception (S02) are essentially carried out at right angles to the surface of the quasi-continuous ingot, and wherein when determining (S04) at least one of the two distances, trigonometric functions are also used to correct the influence of angular deviations of the vertical measurement.

9. The method according to claim 1, wherein The aperture is dimensioned in such a way that an effective aperture angle for the emission device results which is at most 80% of the emission aperture angle of the emission device.

10. The method according to claim 1 or 9, wherein The distance between the emitting device and the wall (51, 52, 61, 62) is at least 10 cm.

11. The method according to any one of claims 1 to 4, wherein The quasi-continuous strand is produced in a continuous casting method.

12. The method according to any one of claims 1 to 4, wherein The transmitting device and / or the receiving device are arranged immediately after the outlet of the mold.

13. The method according to any one of claims 1 to 4, wherein The transmitting device and the receiving device include a common radar transceiver.

14. The method according to claim 13, wherein The transmitting device and / or the receiving device includes a horn antenna and / or a phased array antenna.

15. A device for casting metal to form a quasi-continuous strand (100, 100b) in the field of continuous casting methods and for contactlessly determining at least one property of an at least partially molten quasi-continuous strand (100, 100b) during casting of the quasi-continuous strand (100, 100b), the device comprising: - a mold (4) suitable for shaping the quasi-continuously cast strand (100, 100b), a cooling zone (K) in which the quasi-continuously cast strand (100, 100b) is cooled, so that a gradual hardening of the quasi-continuously cast strand (100, 100b) can be achieved, a transmitting device (11, 13, 31, 32) configured to transmit a first radar signal (102, 103) in the form of radiation, a receiving device (12, 13, 31, 32) arranged to receive a second radar signal (101, 103), wherein the second radar signal (101, 103) is generated at least in part by the interaction of the first radar signal (102, 103) with a region of the quasi-continuously cast strand (100, 100b) in the cooling zone (K) or upstream of the cooling zone (K), a data processing unit configured to determine at least one property of the quasi-continuously cast strand (100, 100b) based on the second radar signal (101, 103), wherein the transmitting device (11, 13, 31, 32) and the receiving device (12, 13, 31, 32) are arranged such that they determine at least one property of the quasi-continuously cast strand (100, 100b) in or upstream of the cooling zone (K), A wall (51, 52, 61, 62) is arranged between the transmitting device and the quasi-continuously cast strand, wherein the wall has pores (7) through which signal propagation is possible.

16. Use of a transmitting device (11, 13, 31, 32) and a receiving device (12, 13, 31, 32) for radar signals (101, 102, 103) for contactlessly determining at least one property of an at least partially melted quasi-continuously cast strand (100, 100b) during a casting process of the quasi-continuously cast strand (100, 100b), the quasi-continuously cast strand being cooled in a cooling zone (K), wherein a gradual hardening of the quasi-continuously cast strand (100, 100b) can be achieved. The transmitting device (11, 13, 31, 32) and the receiving device (12, 13, 31, 32) are arranged so that they determine at least one property of the quasi-continuously cast strand (100, 100b) in the cooling zone (K) or upstream of the cooling zone (K), and the at least one property of the quasi-continuously cast strand is selected from the group consisting of distance, width, thickness, density, temperature and uniformity. A wall (51, 52, 61, 62) is arranged between the transmitting device and the quasi-continuously cast strand, wherein the wall has pores (7) through which signal propagation can be achieved.

17. Use of the method according to any one of claims 1 to 14 or the device according to claim 15 for contactless determination of oscillation marks of a quasi-continuously cast strand.

Images