Method for controlling roll gap in continuous casting machine

Abstract

To manage a roll spacing at higher precision even if irregular movement is generated at a dummy bar on a machine side.SOLUTION: A roll spacing Rs is acquired from plural measurement data measured with a roll spacing meter 10 along with the movement of a dummy bar 7, and a measurement time corresponding to the acquired roll spacing RS is successively acquired. Then, a movement distance from a pair of standard rolls to a pair of support rolled as targets is obtained from a lapse time from the pair of standard rolls to the pair of support rolls obtained based on the measurement time and the movement speed of the dummy bar 7, and the adequacy of the roll spacing RS of the pair of support rolls as targets is determined from a comparison between the movement distance and a standard distance.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a technique for managing roll gaps, such as the validity of the measured roll gap between each pair of rolls in a continuous casting machine. [Background technology]

[0002] A continuous casting machine is a facility for producing slabs of a target size, and the roll gap between each pair of support rolls in a roll group consisting of a plurality of pairs of support rolls that support and guide the casting by drawing is set precisely for quality. This roll gap is measured by a roll gap meter attached to the dummy bar while the dummy bar is being inserted before the start of casting and while the dummy bar is being withdrawn after the start of casting. Then, after it is confirmed that each measured roll gap is within the allowable range of each preset roll gap setting value, it is used to guarantee the soundness of the equipment such as the support rolls and bearings and the quality of the slab.

[0003] Typically, a dummy bar equipped with a roll gap meter is inserted from above into a guideway in which a number of support roll pairs that support and guide the slab are formed. As the dummy bar moves through the guideway, measurement data sequentially measured by the roll gap meter is transmitted to the ground side (outside the continuous casting machine) by wireless communication between the dummy bar machine and the ground. In addition, since the roll gap meter is placed inside the continuous casting machine during roll gap measurement, it is physically impossible to accurately check the measurement status of the roll gap meter from outside the machine. Also, the measurement data transmitted to the ground alone cannot confirm which support roll pair was measured.

[0004] Therefore, a conventional method is sometimes used in which tracking information synchronized with the measurement data is added to track the measurement roll. For example, Patent Document 1 discloses a method for detecting the roll detection time on the machine side and the roll position passing time on the ground side by synchronizing them. Patent Document 2 discloses a method for tracking the position of a roll gap meter using a ground-side system. Patent Documents 3 to 5 disclose methods for tracking the position of a roll gap meter using the passing timing of special rolls such as pinch rolls. Furthermore, Patent Document 6 discloses a method for installing a distance meter on the roll gap meter and determining which position in the casting direction the roll gap meter has passed from the measurement value of the distance meter. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-78812 A [Patent Document 2] JP 2012-245531 A [Patent Document 3] JP 2004-37089 A [Patent Document 4] Japanese Patent Application Publication No. 10-185505 [Patent Document 5] Japanese Patent Application Publication No. 58-81545 [Patent Document 6] JP 2014-226672 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, during roll interval measurement, the dummy bar on which the roll interval meter is installed may slip between the rolls or the dummy bar may meander. For this reason, the on-board side may not be able to measure the relevant roll at the timing assumed by the ground-side tracking. For this reason, when tracking processing is performed based on the ground-side system as in Patent Documents 1 and 2, there are cases where the roll interval measurement does not go well.

[0007] Furthermore, if the above-mentioned problem occurs during measurement of the special roll, there are cases where the roll interval cannot be measured properly in tracking processes based on the special roll as in Patent Documents 3-5. In addition, since the dummy bar passes through the interior of the continuous casting machine, it is often exposed to heat and water. Therefore, installing new instrumentation devices on the dummy bar, as in Patent Document 6, places a burden on equipment maintenance. In other words, it is preferable to improve the measurement accuracy of the roll gap by processing outside the machine.

[0008] The present invention has been made with attention to the above-mentioned points, and aims to more accurately manage the roll spacing even when irregular movement of the dummy bar occurs on the machine, such as slippage between the dummy bar and the support rolls or meandering of the dummy bar. [Means for solving the problem]

[0009] In order to solve the problem, one aspect of the present invention is a method for managing the roll intervals of each support roll pair in a continuous casting machine in which a plurality of support roll pairs, each consisting of a pair of support rolls, are arranged along a casting direction, and a cast strip to be pulled out of a mold is supported and guided by the plurality of support roll pairs, the method including a roll interval acquisition step in which a dummy bar having a roll interval meter installed thereon for measuring the roll intervals of the support roll pairs moves along a guide path formed by the plurality of support roll pairs, and the roll intervals of each support roll pair are acquired based on a plurality of measurement data measured by the roll interval meter as the dummy bar moves, a measurement time acquisition step in which a measurement time is acquired which is the time when the measurement data corresponding to the acquired roll interval is measured, and a measurement time acquisition step in which a measurement time is acquired for each support roll of a target and a roll-to-roll distance acquisition step of determining a moving distance from the reference roll pair to the target support roll pair based on the elapsed time from the measurement time of a reference roll pair, which is a support roll pair located upstream of the target roll pair, to the measurement time of the target support roll pair and on the moving speed of the dummy bar; and a validity determination step of determining the validity of the roll spacing acquired in the roll spacing acquisition step as the roll spacing of the target support roll pair by comparing the moving distance with a preset reference distance, wherein if it is determined in the validity determination step that the roll spacing is not valid, the roll spacing value acquired in the roll spacing acquisition step as the roll spacing of the target support roll pair is regarded as an incorrect value. Effect of the Invention

[0010] According to the aspects of the present invention, even if the dummy bar experiences irregular movements such as slippage between the dummy bar and the rolls or meandering of the dummy bar, it is possible to more reliably link the measured support roll pair with the measurement data. Therefore, by controlling the roll gap according to the aspects of the present invention, it is possible to quickly determine the equipment soundness of the continuous casting machine, such as the support rolls that support and guide the slab and the roll bearings, and to quickly guarantee the quality of the slab, thereby enabling stable and efficient continuous casting. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram illustrating a continuous casting machine according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram illustrating a configuration of a roll gap meter. [Diagram 3] FIG. 11 is a diagram illustrating a transition of measurement data of a roll gap meter. [Figure 4] FIG. 2 is a diagram showing a roll gap management device. [Diagram 5] FIG. 2 is a diagram showing a processing block of a roll gap management device. [Figure 6] FIG. 11 is a diagram illustrating an example of data. [Figure 7] FIG. 11 is a diagram illustrating an example of data. [Figure 8] FIG. 1 is a diagram for explaining machine dimensions (physical distances) etc. [Figure 9] FIG. 13 is a schematic diagram for explaining the validity of the roll interval using the moving distance at the measurement time. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Next, an embodiment of the present invention will be described with reference to the drawings. (Continuous casting machine 100) FIG. 1 is a schematic diagram of a continuous casting machine 100 suitable for use in carrying out the present invention. In FIG. 1, reference numeral 1 denotes a tundish. The tundish 1 holds molten metal 2 to be used for continuous casting. The molten metal 2 in the tundish 1 is supplied to a mold 5 for continuous casting via a sliding nozzle 3 and a submerged nozzle 4. A plurality of support roll pairs, each of which is made up of a pair of support rolls 6 arranged in a direction intersecting the casting direction, are arranged along the casting direction. The cast slab S cast in the mold 5 is supported and guided by a roll group made up of a plurality of support roll pairs arranged in the casting direction, and is drawn out. The roll group made up of a plurality of support roll pairs is arranged in a secondary cooling zone. Reference numeral 8 denotes a pinch roll provided downstream of the continuous casting machine 100.

[0013] The dummy bar 7 guides the initial casting portion of the cast strand S cast in the mold 5 to a pinch roll 8 provided downstream of the continuous casting machine 100. The dummy bar 7 is inserted from above into a guide path formed by a plurality of support roll pairs and moves along the guide path, i.e., along the casting direction.

[0014] (Total of 10 roll intervals) One or more roll interval meters 10 are provided along the longitudinal direction of the dummy bar 7. In FIG. 2, one roll interval meter 10 is shown. The roll gap meter 10 is a device that measures the gap between pairs of support rolls 6, i.e., the roll gap between each pair of support rolls. The roll gap meter 10 is not limited to the configuration shown in Fig. 2, and any known roll gap meter can be used. The roll interval meter 10 shown in FIG. 2 includes a pair of movable arms 10A as an operating unit, a rotation detection unit 10B, a measurement unit 10C, and a wireless device 10D.

[0015] The pair of arms 10A are arranged to be rotatable in the opposing direction of the pair of support rolls 6, and are biased in the direction of separating the pair of arms 10A. As a result, the pair of arms 10A rotate and displace until they come into contact with the opposing support rolls 6, and the rotation angle of the pair of arms 10A is detected by the rotation detection unit 10B. The rotation angle detected by the rotation detection unit 10B changes depending on the change in the contact position of the arms 10A with the support rolls 6 as the dummy bar 7 moves in the casting direction. The measurement unit 10C transmits measurement data corresponding to the rotation angle detected by the rotation detection unit 10B at a predetermined sampling period to the roll gap management device by wireless communication using the wireless device 10D (see FIG. 4).

[0016] Here, a method for measuring the roll gap RS by the roll gap meter 10 will be described. The roll interval meter 10 moves along the line of paired support rolls 6 as the dummy bar 7 moves, and the rotation angle continuously decreases as the pair of arms 10A enter between one of the paired support rolls 6, and then the rotation angle continuously increases as the pair of arms 10A exit the one of the paired support rolls 6. As the dummy bar 7 moves, the detected rotation angle changes periodically, so that the measurement data from the roll interval meter 10 fluctuates as the dummy bar 7 moves, as shown in FIG.

[0017] Among the detected rotation angles (corresponding to the gap between the support rolls 6), the rotation angle (peak value) at which the rotation angle is smallest is set as the rotation angle corresponding to the roll interval RS between the target support roll pair. The rotation angle is converted into a distance, whereby the roll interval RS of the target support roll pair can be obtained. In this manner, the roll interval RS of each support roll pair arranged in the casting direction can be detected in order from the upstream side based on the periodic wave-like change in the rotation angle accompanying the movement of the dummy bar 7. The measurement data may be information on the rotation angle between the pair of arms 10A itself, or may be the amount of rotational displacement of the arm 10A from the initial position. Either of these can be converted into distance information. The measurement data may be a value obtained by converting the rotation angle information into distance information. The measurement data to be transmitted may also be added with the measurement time at which the measurement data to be transmitted was acquired.

[0018] (Roll gap management device 20) The roll gap management device 20 is disposed outside the continuous casting machine 100, such as on the ground. The roll gap management device 20 may be configured with one or more computer devices, and a calculation unit of the roll gap management device 20 may be configured with a program executable by a computer, etc. As shown in Fig. 4, the roll gap management device 20 acquires measurement data from the roll gap meter 10 via a wireless device 12. In addition, the roll gap management device 20 obtains information on the moving speed (casting speed) of the dummy bar 7 and information on the machine dimensions, which are the physical distance along the casting direction between a pair of support rolls aligned in the casting direction, from a higher-level system 11 (higher-level computer). As shown in FIG. 5, the roll spacing management device 20 includes a data acquisition unit 20A, a roll spacing acquisition unit 20B, a measurement time acquisition unit 20C, a roll-to-roll distance acquisition unit 20D, a validity determination unit 20E, a roll recognition determination unit 20F, and a reference roll pair setting unit 20G.

[0019] <Data Acquisition Unit 20A> The data acquisition unit 20A inputs the measurement data from the roll interval meter 10 at a preset sampling period, and acquires data of the measurement time, which is the time when the measurement data is input, in synchronization with the input of the measurement data. If the measurement data from the roll interval meter 10 is accompanied by data of the measurement time when the measurement data is acquired, there is no need to acquire the measurement time again. The data acquisition unit 20A sequentially stores the acquired data (measurement data, measurement time data) in a storage unit, which may be, for example, a database.

[0020] <Roll interval acquisition unit 20B> The roll interval acquisition unit 20B executes a process of acquiring the roll interval RS between each pair of support rolls based on time-series information of a plurality of pieces of measurement data measured by the roll interval meter 10 as the dummy bar 7 moves. As described above, the roll interval RS is the minimum interval value between the opposing support rolls 6. As shown in FIG. 3, the values ​​of the multiple measurement data change periodically, and the roll spacing acquisition unit 20B sequentially acquires the values ​​of the measurement data at the inflection point positions (peak positions) where the measurement data are minimum, as information on the roll spacing RS of the target support roll pair.

[0021] That is, the roll spacing acquisition unit 20B sequentially obtains peak values ​​that provide the shortest distances from the measurement data continuously acquired by the data acquisition unit 20A, converts the obtained peak values ​​into distances, and sets the distances as the roll spacing RS values ​​of the support roll pairs. If there is no erroneous detection, the roll spacing acquisition unit 20B acquires the roll spacing RS of the support roll pairs sequentially, starting from the most upstream support roll pair. Here, the measurement data from the roll interval meter 10 may be a value obtained by converting the rotation angle into a distance, as described above. Also, when the measurement data from the roll interval meter 10 is a rotation angle, for example, it is sufficient to find the rotation angle at which the rotation angle is minimum, and convert only that rotation angle into a distance.

[0022] <Measurement time acquisition unit 20C> The measurement time acquisition unit 20C acquires a measurement time, which is the time when the measurement data corresponding to the acquired roll interval RS is measured. In other words, the measurement time acquisition unit 20C acquires the time when the measurement data corresponding to the roll interval RS acquired by the roll interval acquisition unit 20B is acquired as the measurement time. Note that the roll interval acquisition unit 20B may also function as the measurement time acquisition unit 20C. Here, the roll interval RS obtained by the roll interval obtaining unit 20B and the measurement time obtained by the measurement time obtaining unit 20C are associated with each other and sequentially stored in the storage unit as data such as that shown in FIG.

[0023] In addition, as the dummy bar 7 moves, the roll spacing RS of the support roll pairs is calculated in sequence by processing of the roll spacing acquisition unit 20B and the measurement time acquisition unit 20C, data such as that shown in FIG. 6 is stored in the memory unit, and information such as that shown in FIG. 7 is stored in the memory unit in association with the numbers of the support roll pairs in sequence from the upstream side. Here, the processing of the roll interval acquisition unit 20D and the measurement time acquisition unit 20C and the processing after the roll interval acquisition unit 20D described below may be configured to be executed as a series of processes, or the processing after the roll interval acquisition unit 20D may be executed after the processing of the roll interval acquisition unit 20D and the measurement time acquisition unit 20C is completed. From the viewpoint of shortening the processing time, it is preferable to execute them as a series of processes.

[0024] <Roll Distance Acquisition Unit 20D> The target support roll pair is changed in sequence from the most upstream support roll pair toward the downstream, and the processing is performed. The roll distance acquisition unit 20D performs a process to calculate the movement distance from the reference roll pair to the currently targeted support roll pair based on the elapsed time from the measurement time at a reference roll pair, which is a support roll pair located upstream of the target support roll pair, to the measurement time at the target support roll pair, and the movement speed (casting speed) of the dummy bar 7. The moving speed (casting speed) of the dummy bar 7 may be, for example, a sequential casting speed acquired from a host system, or may be a constant speed set in advance.

[0025] Here, the roll interval acquisition unit 20B and the measurement time acquisition unit 20C process the multiple support roll pairs in order starting from the upstream support roll pair, and data pairs each including the roll interval RS and the measurement time are stored in the storage unit in order as shown in Fig. 7. In Fig. 7, "NO." indicates roll numbers assigned from upstream to downstream, with smaller numbers corresponding to more upstream support roll pairs. The roll distance acquisition unit 20D and the validity determination unit 20E also execute processing in order starting from the upstream support roll pair, and the processing of the roll distance acquisition unit 20D and the processing of the validity determination unit 20E are executed as a series of processing.

[0026] The reference roll pair is initially set to the support roll pair immediately preceding the target support roll pair. If the target support roll pair number is #(N+1), the reference support roll pair number is #(N) by default. Here, the case where the number of the target support roll pair is #(N+1) will be described as an example. First, the roll distance acquisition unit 20D acquires the measurement time of the target support roll pair #(N+1) and the measurement time of the reference support roll pair from the storage unit. Regarding the validity of the interval If it is determined to be valid, the reference support roll pair is designated as #(N).

[0027] Next, the roll-to-roll distance acquisition unit 20D subtracts the measurement time (reference time) of the reference roll pair #(N) from the measurement time of the target support roll pair #(N+1) to obtain the movement time of the dummy bar 7 from the reference roll pair #(N) to the target support roll pair #(N+1). Next, the roll-to-roll distance acquisition unit 20D multiplies the obtained movement time by the movement speed (casting speed) of the dummy bar 7 to calculate the roll-to-roll distance between the reference roll pair #(N) and the target support roll pair #(N+1) based on the measurement position (measurement time) of the roll gap RS.

[0028] <Validity Determination Unit 20E> The validity determination unit 20E determines the validity of the roll spacing RS obtained by the roll spacing acquisition unit 20B as the roll spacing RS of the target support roll pair #(N+1) by comparing the moving distance obtained by the roll distance acquisition unit 20D with a preset reference distance. The validity determination is, for example, a determination of the validity of the obtained value of the roll spacing RS or the validity of the measurement position at which the roll spacing RS is obtained.

[0029] The reference distance is determined from the physical dimensions, which are the dimensions of the physical arrangement of multiple support roll pairs based on the design conditions of the continuous casting machine 100. The physical dimensions are the physical distance between the support roll pairs in the casting direction. In other words, the reference distance is the physical distance from the reference roll pair to the target support roll pair. If there is distance information between adjacent support roll pairs in the casting direction, the reference distance can be determined. In the region where the support rolls 6 are arranged in an arc shape, the distance between adjacent support roll pairs in the casting direction is the distance along the casting direction at the center of the guideway formed by the multiple support roll pairs. In other words, the reference distance is the distance measured in a direction along the trajectory along which the dummy bar 7 moves.

[0030] In the present embodiment, the validity determination unit 20E determines whether the absolute value of the difference between the moving distance obtained for the corresponding support roll pair #(N+1) and the reference distance is within a first threshold value set in advance. If the absolute value of the difference is within the first threshold value, the validity determination unit 20E determines that the roll interval RS acquired for the target support roll 6#(N+1) is valid, and sets a flag (Yes) indicating that the opposing support roll pair #(N+1) is valid, as shown in FIG. 7. On the other hand, if the absolute value of the difference is greater than the first threshold value, the validity determination unit 20E determines that the roll interval RS acquired for the target support roll 6#(N+1) is not valid, and sets a flag (No) indicating that the opposing support roll pair #(N+1) is not valid.

[0031] The absolute value of the difference corresponds to the amount of deviation in the casting direction from the initial position at the opposing positions where the pair of support rolls 6 are measured, and the value of the roll gap RS includes an error corresponding to the amount of deviation. The first threshold value can be set so that the deviation corresponds to an allowable value for this error. The first threshold value is, for example, 5% of the reference distance (machine dimension). The normal roll range of the measurement position is set to within ±5% of the reference distance for the following reasons.

[0032] A schematic diagram of the distance between the support rolls 6 arranged in the casting direction is shown in Fig. 8. Although the adjacent support rolls 6 are not actually in contact with each other, in Fig. 5, the adjacent support rolls 6 are shown as being in contact with each other for the sake of simplicity. In Fig. 8, reference numeral 30 denotes the roll radius, reference numeral 31 denotes the machine dimension between the rolls, reference numeral 32 denotes the roll chord length, and reference numeral 33 denotes the roll arrow height. The roll arrow height 33 is the error in the roll interval RS. Consider an actual continuous casting machine 100 in which the roll radius 30 of each of the adjacent support rolls 62 is 250 mm, for example. In this case, the machine dimension 31 is 500 mm, and if the roll chord length 32 is 5% of the machine dimension 31, it is 25 mm, and the roll arrow height 33 is approximately 0.3 mm. Since the roll spacing RS is measured and controlled within a range of at most about ±1.5 mm, the roll arrow height 33 of 0.3 mm, which is 10% of that, is set as the allowable value, and in this embodiment, the absolute difference is set to within ±5% of the machine dimension.

[0033] <Roll recognition determination unit 20F> The roll recognition determination unit 20F determines whether the value of the roll interval RS acquired by the roll interval acquisition unit 20B is the value obtained by determining the interval between the pair of support rolls 6 or not. The roll recognition determination unit 20F determines whether the absolute value of the difference between the moving distance obtained for the corresponding support roll pair #(N+1) and the reference distance is within a second threshold value that is greater than the first threshold value. When the roll recognition determination unit 20F determines that the absolute value of the difference is within the second threshold value, it determines that the roll interval RS acquired by the roll interval acquisition unit 20B for the corresponding support roll pair #(N+1) is a measurement of the interval between the support rolls 6, that is, it determines that the roll interval RS is within the roll recognition range of the target support roll pair. On the other hand, when the roll recognition determination unit 20F determines that the absolute value of the difference is greater than the second threshold value, it determines that the roll interval RS acquired by the roll interval acquisition unit 20B for the corresponding support roll pair #(N+1) is a failure in measuring the interval between the support rolls 6, that is, it determines that the roll interval RS is outside the roll recognition range of the target support roll pair. The second threshold is, for example, 50% of the reference distance.

[0034] Furthermore, when the roll recognition determination unit 20F determines that the movement distance is outside the roll recognition range (: absolute value of the difference>second threshold value) and is shorter than the reference distance, it determines that the measurement was erroneously performed due to roll overdetection, and ignores the data of the roll interval RS acquired by the roll interval acquisition unit 20B as the roll interval RS of the target support roll pair #(N+1). That is, it discards the data of the current support roll pair #(N+1), and continues the process by using the roll interval RS obtained by the roll interval acquisition unit 20B for the next support roll pair as the data of the support roll pair #(N+1). In addition, if the roll recognition determination unit 20F determines that the movement distance is outside the roll recognition range (if the absolute value of the difference is greater than the second threshold value) and the movement distance is longer than the reference distance, it determines that the roll measurement of the currently targeted support roll pair #(N+1) has failed or been undetected, and sets the value of the roll spacing RS of the support roll 6 of #(N+1) to null (NULL).

[0035] <Reference roll pair setting unit 20G> The reference roll pair setting unit 20G sets a reference roll pair to be used for the support roll pair targeted by the roll-to-roll distance acquisition unit 20D. The reference roll pair setting unit 20G sets a support roll pair that is upstream of the support roll pair targeted by the roll interval acquisition unit 20B and whose validity is determined to be correct by the validity determination unit 20E as the reference roll pair. At this time, the reference roll is set to the support roll pair that is closest to the support roll pair targeted by the roll-to-roll distance acquisition unit 20D, that is, the most downstream support roll pair among the support roll pairs whose validity is determined to be correct by the validity determination unit 20E.

[0036] In the reference roll pair setting unit 20G of this embodiment, when the validity judgment unit 20E judges that the validity of the roll spacing RS of the target support roll pair #(N+1) is correct, the reference roll pair to be used when the next support roll pair #(N+2) after the support roll pair #(N+1) whose validity has been judged is set as the target support roll pair is updated to the support roll pair #(N+1) located just before the target support roll pair #(N+2). On the other hand, when the validity determination unit 20E determines that the roll interval RS of the target support roll pair #(N+1) is not valid, the reference roll pair setting unit 20G does not update the reference roll pair. As a result, the reference roll pair becomes the support roll pair located most downstream among the support roll pairs selected from the support roll pairs located two or more before the target support roll pair.

[0037] Here, if the role recognition determination unit 20F determines that the role recognition range is exceeded (if the absolute value of the difference is greater than the second threshold) and the movement distance is shorter than the reference distance, the data itself is discarded, and therefore processing by the reference role pair setting unit 20G is unnecessary. Furthermore, the roll interval acquisition unit 20B constitutes a roll interval RS acquisition step. The measurement time acquisition unit 20C constitutes a measurement time acquisition step. The roll distance acquisition unit 20D constitutes a roll distance acquisition step. The validity determination unit 20E constitutes a validity determination step. The roll recognition determination unit 20F constitutes a roll recognition determination step. The reference roll pair setting unit 20G constitutes a reference roll pair setting step.

[0038] (Operation etc.) In this embodiment, the validity of the calculated value of the roll spacing RS of each support roll pair is determined by comparing the travel distance based on the elapsed time from the upstream support roll pair for which a validity determination has already been made with the previously determined physical distance (separation distance). This makes it possible to accurately determine the validity of the roll spacing RS of each support roll pair even if irregular movement of the dummy bar 7 occurs on the machine, such as slippage between the dummy bar 7 and the roll or meandering of the dummy bar 7 (see Figure 9). Furthermore, since this validity determination can be performed, for example, by simply modifying the control software, the burden on facility management can be reduced. Furthermore, by using the elapsed time in the same manner as described above to determine whether the position at which the roll interval RS is measured is within the roll recognition range, it is possible to determine the tracking deviation of the position of the measured support roll pair even if irregular movement of the dummy bar 7 occurs.

[0039] (others) The present disclosure may also have the following configuration. (1) A method for managing the roll gap of each pair of support rolls in a continuous casting machine 100 in which a plurality of pairs of support rolls, each consisting of a pair of support rolls 6, are arranged along the casting direction and a cast strip being pulled out of a mold is supported and guided by the plurality of pairs of support rolls, a dummy bar having a roll interval meter for measuring the roll interval between the support roll pairs, the dummy bar moving along a guideway formed by the plurality of support roll pairs; a roll interval acquisition step of acquiring roll intervals between each pair of support rolls based on a plurality of measurement data measured by the roll interval meter in association with the movement of the dummy bar; a measurement time acquisition step of acquiring a measurement time which is a time at which the measurement data corresponding to the acquired roll interval was measured; a roll-to-roll distance acquisition step of determining a moving distance from the reference roll pair to the target support roll pair based on an elapsed time from the measurement time of a reference roll pair, which is a support roll pair located upstream of the target support roll pair, to the measurement time of the target support roll pair and a moving speed of the dummy bar; a validity determination step of determining the validity of the roll interval acquired in the roll interval acquisition step as the roll interval of the target support roll pair by comparing the moving distance with a preset reference distance, If it is determined in the validity determination step that the validity is not present, the value of the roll spacing acquired in the roll spacing acquisition step as the roll spacing of the target support roll pair is regarded as an incorrect value.

[0040] (2) further comprising a reference role pair setting step; The above reference role pair setting step includes: When it is determined in the validity determination step that the validity of the roll interval is correct, the reference roll pair to be used when the next support roll pair after the support roll pair whose validity has been determined is set as the target support roll pair is set as the support roll pair located immediately before the target support roll pair, If the validity of the roll spacing is determined to be incorrect in the validity determination step, the reference roll pair to be used when the next support roll pair after the support roll pair whose validity has been determined to be the target support roll pair is a support roll pair selected from the support roll pairs located two or more positions before the target support roll pair.

[0041] (3) In the reference roll pair setting step, a support roll pair selected from support roll pairs located two or more positions before the target support roll pair is set as the reference roll pair, which is upstream of the target support roll pair and located most downstream among the support roll pairs whose roll spacing is determined to be correct in the validity determination step. (4) The reference distance is determined from the physical dimensions, which are the dimensions of the physical arrangement of the plurality of support roll pairs.

[0042] (5) the reference distance is a physical distance from the reference roll pair to the target support roll pair, In the validity determination step, if the absolute value of the difference between the movement distance and the reference distance is within a preset first threshold value, it is determined that the inter-roll distance obtained for the target support roll 6 is valid. (6) The method further includes a roll recognition determination step of determining that the roll spacing acquired in the roll spacing acquisition step is the measurement of the spacing between support rolls 6 if the absolute value of the difference is within a second threshold value greater than the first threshold value.

[0043] (7) When the absolute value of the difference is determined to be greater than the second threshold value in the roll recognition determination step and the moving distance obtained in the roll-to-roll distance acquisition step is determined to be shorter than the reference distance, the information of the support roll pair is deemed not to be information measuring the distance between the support roll pair, and the roll distance data obtained in the roll distance acquisition step is discarded. (8) The processes of the roll interval acquisition step, the measurement time acquisition step, the roll distance acquisition step, the validity determination step, and the roll recognition determination step are executed by a computer. EXAMPLES

[0044] Next, examples based on this embodiment will be described. The target was a continuous casting machine 100 equipped with 158 support roll pairs with roll diameters ranging from 250 to 350 mm. A dummy bar 7 was inserted from above to measure the roll spacing RS for each support roll pair. In the examples, the roll spacing RS for each pair of support rolls was measured using the method described in the embodiment. On the other hand, in the comparative example, a tracking process was performed based on the moving speed of the dummy bar 7 on the ground, and the roll interval RS for each pair of support rolls was measured from the measurement data from the roll interval meter 10.

[0045] The number of erroneous measurements by the roll spacing meter 10 was compared between the working example and the comparative example. An erroneous measurement is a measurement in which the measurement result of the roll spacing meter 10 exceeds the allowable value of the roll spacing RS setting, resulting in an abnormality, even though there is no abnormality in the actually measured roll spacing RS. The experiment was performed 100 times for each example, and the average number of erroneous measurements was compared. According to this experiment, it was confirmed that the number of erroneous measurements was reduced to less than half in the embodiment compared to the comparative example. This is presumably because, in the embodiment, the influence of deviation from ground tracking is suppressed and tracking processing can be performed, eliminating tracking failures due to tracking deviation on the ground side. [Explanation of symbols]

[0046] 2 Support roll 6 5. Mold 7 Dummy Bar 10 Roll gap meter 10A Arm 10B Rotation detection unit 10C Measurement section 10D wireless device 11 Upper System 20 Roll gap control device 20A Data acquisition section 20B Roll interval acquisition unit 20C Measurement time acquisition unit 20D Roll Distance Acquisition Unit 20E Validity Judgment Section 20F Role Recognition Judgment Unit 20G Reference Role Pair Setting Section RS Roll Interval S Casting

Claims

1. A method for managing a roll gap between each pair of support rolls in a continuous casting machine in which a plurality of pairs of support rolls are arranged along a casting direction and a cast strip being pulled out of a mold is supported and guided by the plurality of pairs of support rolls, the method comprising: a dummy bar having a roll interval meter for measuring the roll interval between the support roll pairs, the dummy bar moving along a guideway formed by the plurality of support roll pairs; a roll interval acquisition step of acquiring roll intervals between each pair of support rolls based on a plurality of measurement data measured by the roll interval meter in association with the movement of the dummy bar; a measurement time acquisition step of acquiring a measurement time which is a time at which the measurement data corresponding to the acquired roll interval was measured; a roll-to-roll distance acquisition step of determining a moving distance from the reference roll pair to the target support roll pair based on an elapsed time from the measurement time of a reference roll pair, which is a support roll pair located upstream of the target support roll pair, to the measurement time of the target support roll pair and a moving speed of the dummy bar; a validity determination step of determining whether or not the roll interval acquired in the roll interval acquisition step is valid as the roll interval of the target support roll pair by comparing the moving distance with a preset reference distance, If it is determined that the validity is not valid in the validity determination step, the value of the roll spacing acquired in the roll spacing acquisition step as the roll spacing of the target support roll pair is regarded as an incorrect value. A method for managing roll intervals.

2. Further, a reference role pair setting step is provided, The above reference role pair setting step includes: When it is determined that there is validity in the validity determination step, the reference roll pair to be used when the next support roll pair of the support roll pair whose validity has been determined is set as the target support roll pair is set as the support roll pair located one before the target support roll pair, When it is determined that the validity is not present in the validity determination step, the reference roll pair to be used when the next support roll pair of the support roll pair determined to be valid is set to the target support roll pair, the reference roll pair to be used is set to a support roll pair selected from the support roll pairs located two or more before the target support roll pair.

2. The method for managing the roll gap according to claim 1 .

3. In the reference roll pair setting step, the support roll pair selected from the support roll pairs located two or more before the target support roll pair is set to the support roll pair located upstream of the target support roll pair and the most downstream of the support roll pairs determined to be valid in the validity determination step, as the reference roll pair.

3. The method for managing the roll gap according to claim 2.

4. The reference distance is determined from physical dimensions, which are dimensions of the physical arrangement of the plurality of support roll pairs.

2. The method for managing the roll gap according to claim 1 .

5. the reference distance is a physical distance from the reference roll pair to the target support roll pair, The validity determination step determines that the roll interval obtained for the target support roll is valid if an absolute value of a difference between the movement distance and the reference distance is within a first threshold value set in advance.

5. The method for managing the roll gap according to claim 4.

6. a roll recognition determination step of determining that the roll interval acquired in the roll interval acquisition step is a measurement of an interval between support rolls if the absolute value of the difference is within a second threshold value that is greater than the first threshold value; 6. The method for managing the roll gap according to claim 5.

7. When the absolute value of the difference is determined to be greater than the second threshold value in the roll recognition determination step, and the moving distance obtained in the roll-to-roll distance acquisition step is determined to be shorter than the reference distance, the information on the support roll pair is deemed not to be information measuring the distance between the support roll pair, and the roll distance data acquired in the roll distance acquisition step is discarded.

7. The method for managing the roll gap according to claim 6.

8. The processes of the roll interval acquisition step, the measurement time acquisition step, the roll distance acquisition step, the validity determination step, and the roll recognition determination step are executed by a computer. The method for managing the roll gap according to any one of claims 1 to 7.

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