JP7167890B2 - Cast slab cut length control method, cast slab cut length control device, and cast slab manufacturing method - Google Patents

Description

The present invention relates to a casting slab cutting length control method, a casting slab cutting length control device, and a casting slab manufacturing method.

In continuous casting, the target length (cutting length) of the cast slab to be cut is determined so as to match the target weight obtained by adding a margin (additional weight) to the required weight required in the subsequent process. It is obtained from the nominal unit weight and a thermal dimension correction coefficient for correcting the nominal unit weight according to the target weight. Here, the nominal unit weight is the weight per unit length of the strand obtained using the specific gravity determined from the cross-sectional area of the mold and the composition of the molten steel (component of the slab). Since it changes immediately after being drawn and after being cooled, the unit weight of the strand immediately before cutting is corrected using the thermal dimension correction coefficient, and the cut length is calculated so as to satisfy the above target weight. However, there is variation in the weight of the slab after it has actually been cut.

In order to avoid such a situation, a method of correcting the cutting length by dividing the target length by a cutting correction coefficient empirically obtained by the operator is sometimes adopted. For example, at the start of casting, the operator inputs a value according to the operator's empirical rule for the cutting correction coefficient, and the operator corrects the cutting correction coefficient according to the weighing results of 3 to 4 slabs, and then the margin reaches the target value. The method of operation is that the operator continues to adjust the cutting correction factor directly to bring it closer.

However, in such a method of determining the cutting length, care is taken not to generate nonconforming materials due to insufficient weight, so the added weight ratio representing the actually added margin (= (actual weight of cast slab - cast slab (required weight of slab)/required weight of cast slab) tends to increase, resulting in a problem of low yield. Also, less experienced operators need to be able to operate without adding excessive margins.

In order to minimize the added weight ratio, first, the accuracy of the unit weight of the strand immediately before cutting is improved so that a cutting correction coefficient close to 1 can always be set (cutting correction need not be performed). Thus far, technical improvements have been made from the viewpoint of performing more accurate thermal size correction by measuring the outer dimensions and temperature of the strand.

In Patent Document 1, when cutting a continuously cast strand into slabs, the slab width is measured with a clamp device, the slab thickness is measured with a length measuring device, and the actual width and actual thickness of the obtained strand and the cutting schedule A slab cutting command length is calculated based on the command mass of the slab, the strand is transported, and when the transport distance reaches the slab cutting command length of the slab to be cut, the strand is clamped to cut the continuously cast slab. A method of doing so is disclosed.

In Patent Document 2, an ultrasonic sensor detects or estimates the crater end position of the cast strand before cutting, and the cast to be cut is detected or estimated based on the relationship between the detected or estimated crater end position and the pre-determined cast strand unit weight. A method is disclosed for correcting the cut length to achieve the target weight of the slab.

In Patent Document 3, a surface temperature measuring device that measures the surface temperature of the strand is installed between the pinch roll and the cutting device, and the surface temperature measured by the surface temperature measuring device for a plurality of cut slabs and the measured weight of each cast slab, an auxiliary coefficient to be multiplied by each casting condition included in the formula for calculating the correction coefficient is obtained, and each auxiliary coefficient and the casting related to the slab to be cut next A method is disclosed for obtaining a correction coefficient to be applied to the calculation of the cut length of the cast slab from the information on the loading conditions.

In Patent Document 4, the in-machine retention time required for the strand at the position corresponding to the slab to be cut to pass through the interior of the continuous casting machine, and the width of the strand measured with a slab width meter immediately before the cutting position. A method for correcting the truncation length based on is disclosed.

In Patent Document 5, the cold length of the slab cut by the cutting length obtained from the required weight is measured, and the process computer determines the hot length of the slab based on the cold length of the slab obtained from the measuring device. A technique is disclosed in which a hot correction coefficient for correcting the length is calculated for each slab, and the hot length corrected by the hot correction coefficient is commanded to a cutting device as the cut length of the slab.

JP 2004-283865 A Japanese Unexamined Patent Application Publication No. 2011-131268 JP 2012-40612 A JP 2014-108449 A JP 2015-58436 A

However, all of the above methods are based on the premise that the strand shape is a perfect rectangular parallelepiped, that is, the cross-sectional shape is a rectangle and each side is kept vertical and extended in the casting direction. Therefore, if the strand shape is not a perfect rectangular parallelepiped, the weight of the cut slab will deviate from the target weight no matter how accurately the thermal dimension correction is performed.

For example, the actual strand shape may exhibit a shape in which the short sides bulge like a barrel (called short-side bulging). In continuous casting of steel, the solidified shell formed in the mold progresses while increasing its thickness, but the solidified shell just after leaving the mold is still thin, so the support of the solidified shell is weak. Then, the solidified shell may bulge outward due to the static pressure of the molten steel existing above. What appears on the short sides of the strand is bulging on the short side, and the width of the bulging portion of the strand is sometimes larger than the width of the mold. That is, in such a case, the cross-sectional area of the strand does not become an accurate value regardless of the appropriateness of the thermal dimension correction coefficient, and the weight of the slab after actually cutting causes an error with respect to the target weight. As a result, there remains the risk that the weight of the slab after cutting will fall below the required weight, and there is the problem that the margin cannot be minimized.

The present invention has been made in view of the above circumstances, and the cast slab can reduce the difference between the target weight of the cast slab and the weight of the actually manufactured cast slab, thereby minimizing the margin. It is an object of the present invention to provide a cutting length control method, a casting slab cutting length control device, and a casting slab manufacturing method.

A casting slab cutting length control method according to the present invention is a casting slab cutting length control method for obtaining a cast slab of a target length by cutting a continuously cast cast strand, wherein the width direction of the cast strand is For short side surfaces on both sides, a measurement step of measuring the width direction position of the short side surface in the thickness direction of the cast strand, and a representative cross-sectional area of the cast strand is calculated using the measured value measured in the measurement step. a determination step of determining the cut length of the cast slab to be cut using the cross-sectional area calculation step and the representative cross-sectional area of the cast strand calculated by the cross-sectional area calculation step; and the cut determined by the determination step cutting the cast slab in length, wherein the measurement of the measuring step is performed at least once within the cutting interval of the cutting step.

A cast slab cutting length control method according to the present invention is the above invention, wherein the weight per unit length of the cast strand is calculated using the representative cross-sectional area of the cast strand calculated by the cross-sectional area calculation step. a weight calculating step, wherein the determining step includes using the weight calculated by the weight calculating step to determine a cut length of the cast slab to be cut.

A casting slab cutting length control method according to the present invention is a casting slab cutting length control method for obtaining a cast slab of a target length by cutting a continuously cast cast strand, wherein the width direction of the cast strand is For the short side surfaces on both sides, a measuring step of measuring the width direction position of the short side surface in the thickness direction of the cast strand, and using the measured value measured in the measuring step, the cross-sectional area of the cast strand is cast. A cross-sectional area calculation step of calculating sequentially with the progress of the cross-sectional area calculation step, a volume calculation step of calculating the volume of the cast strand by integrating the cross-sectional area of the cast strand sequentially calculated by the cross-sectional area calculation step in the casting direction, and the volume calculation a determining step of determining a cut length of the cast slab to be cut using the volume of the cast strand calculated by the step; and a cutting step of cutting the cast slab at the cut length determined by the determining step; wherein the measurement in the measuring step is performed intermittently or continuously within the cutting interval of the cutting step.

A cast slab cutting length control method according to the present invention further includes a weight calculation step of calculating the weight of the cast strand using the volume of the cast strand calculated by the volume calculation step, The determining step includes determining a cut length of the cast slab to be cut using the weight calculated by the weight calculating step.

According to the cast slab cutting length control method according to the present invention, in the above-described invention, the cutting length of the cast slab to be cut is determined by performing a correction by adding a margin to the requested weight of the cast slab in the determining step. It is characterized by determining.

The cast slab cutting length control method according to the present invention is characterized in that, in the above invention, the measurement in the measuring step is performed within a casting direction section from the final support roll of the continuous casting facility to the cutting device.

The cast slab cutting length control method according to the present invention is characterized in that, in the above invention, the measuring step includes a step of measuring the width direction position of the short side face in the thickness direction of the cast strand with a laser rangefinder. Characterized by

A casting slab cutting length control device according to the present invention is a casting slab cutting length control device for cutting a continuously cast cast strand to obtain a cast slab of a target length, wherein the width direction of the cast strand is For the short side surfaces on both sides, a measuring instrument that measures the width direction position of the short side surface in the thickness direction of the cast strand, and the measurement data measured by the measuring instrument are collected, and the representative cross-sectional area of the cast strand is calculated. Determining means for determining the cut length of the cast slab to be cut using the cross-sectional area calculating means for calculating, the representative cross-sectional area of the cast strand calculated by the cross-sectional area calculating means, and the length determined by the determining means a cutting device that cuts the cast slab to the same cutting length, and the measuring device measures the width direction position of the short side surface at least once within the cutting interval of the cutting device. .

A casting slab cutting length control apparatus according to the present invention calculates the weight per unit length of the cast strand using the representative cross-sectional area of the cast strand calculated by the cross-sectional area calculation means in the above invention. weight calculation means, wherein the determination means determines the cut length of the cast slab to be cut using the weight calculated by the weight calculation means.

A casting slab cutting length control device according to the present invention is a casting slab cutting length control device for cutting a continuously cast cast strand to obtain a cast slab of a target length, wherein the width direction of the cast strand is For the short side surfaces on both sides, the cross-sectional area of the cast strand is measured using a measuring instrument that measures the width direction position of the short side surface in the thickness direction of the cast strand, and the measured value measured by the measuring instrument. a cross-sectional area calculating means for calculating sequentially as the process progresses, a volume calculating means for calculating the volume of the cast strand by integrating the cross-sectional areas of the cast strand sequentially calculated by the cross-sectional area calculating means in the casting direction, and the volume calculating determining means for determining a cut length of the cast slab to be cut using the volume of the cast strand calculated by the means; a cutting device for cutting the cast slab at the cut length determined by the determining means; wherein the measuring device intermittently or continuously measures the widthwise position of the short side surface within the cutting interval of the cutting device.

A cast slab cutting length control apparatus according to the present invention further comprises weight calculation means for calculating the weight of the cast strand using the volume of the cast strand calculated by the volume calculation means, The determining means is characterized in that, using the weight calculated by the weight calculating means, the cutting length of the cast slab to be cut is determined.

In the casting slab cutting length control apparatus according to the present invention, in the above invention, the determining means performs a correction by adding a margin to the requested weight of the casting slab to determine the cutting length of the casting slab to be cut. It is characterized by determining.

A casting slab cutting length control apparatus according to the present invention is characterized in that, in the above invention, the measuring device performs the measurement in a section in the casting direction from the last support roll of the continuous casting facility to the cutting device.

A casting slab cutting length control apparatus according to the present invention is characterized in that, in the above invention, the measuring device is a laser range finder.

A method for manufacturing a cast slab according to the present invention is a method for manufacturing a cast slab by cutting a continuously cast cast strand to manufacture a cast slab having a target length. , a measuring step of measuring the width direction position of the short side surface in the thickness direction of the cast strand, and a cross-sectional area calculating step of calculating a representative cross-sectional area of the cast strand using the measured value measured in the measuring step and a determination step of determining the cut length of the cast slab to be cut using the representative cross-sectional area of the cast strand calculated by the cross-sectional area calculation step; and a cutting step of cutting the slab, wherein the measurement in the measuring step is performed at least once within the cutting interval of the cutting step.

A method for manufacturing a cast slab according to the present invention is a method for manufacturing a cast slab by cutting a continuously cast cast strand to manufacture a cast slab having a target length. , the cross-sectional area of the cast strand is sequentially calculated as the casting progresses, using a measurement step of measuring the width direction position of the short side surface in the thickness direction of the cast strand, and the measured value measured in the measurement step. a cross-sectional area calculation step for calculating the cross-sectional area, a volume calculation step for calculating the volume of the cast strand by integrating the cross-sectional areas of the cast strand sequentially calculated by the cross-sectional area calculation step in the casting direction, and the volume calculated by the volume calculation step determining a cut length of the cast slab to be cut using the volume of the cast strand; and cutting the cast slab at the cut length determined by the determining step; The step measurement is intermittently or continuously performed within the cutting interval of the cutting step.

According to the present invention, the width direction positions of the short side surfaces on both sides of the cast strand are measured in the thickness direction of the cast strand, the measured value is used to calculate the representative cross-sectional area of the cast strand, and the cut is made from the representative cross-sectional area. The cut length of the cast slab to be cut can be determined. Thereby, even if the strand shape is not a perfect rectangular parallelepiped, an accurate cut weight reflecting the shape of the cast strand can be calculated, and as a result, the margin can be minimized. Moreover, since the thickness of the cast strand can be accurately grasped by measuring the positions of the short sides on both sides of the cast strand, the cut weight can be calculated more accurately.

FIG. 1 is a schematic configuration diagram of a continuous casting facility in which a cast slab cutting length control method according to an embodiment of the present invention is implemented. FIG. 2 is a schematic diagram for explaining the installation position of the measuring device. FIG. 3 is a schematic diagram for explaining a measuring method using a measuring device. FIG. 4 is a flow chart showing an example of a cast slab cutting length control method.

A casting slab cutting length control method, a casting slab cutting length control device, and a casting slab manufacturing method according to an embodiment of the present invention will be described below with reference to the drawings.

[Configuration of continuous casting equipment]
FIG. 1 is a schematic configuration diagram of a continuous casting facility in which a cast slab cutting length control method according to an embodiment of the present invention is implemented. In this description, regarding the slab cast by the continuous casting facility, the "slab before being cut" is referred to as "cast strand", and the "slab after cutting" is referred to as "cast slab". .

In a continuous casting facility 1, molten steel in a ladle 2 is injected into a tundish 4 through a refractory nozzle 3, and molten steel in the tundish 4 is injected into a mold 6 through a refractory nozzle 3 called an immersion nozzle 5. be done. The mold 6 is vibrated by a vibrating device (not shown) so as not to seize, and the cast strand 7 pulled out from the mold 6 is gradually pulled downward while being supported by the support rolls 8 . A secondary cooling zone is formed in which spray nozzles are arranged in the gap between the support rolls 8 . In the secondary cooling zone, mist-like cooling water is sprayed onto the cast strand 7 from a spray nozzle, thereby cooling the cast strand 7 from the outside. The cast strand 7 is cut into cast slabs 11 by a torch 9, which is a cutting device, after passing through a light reduction belt installed as required. The torch 9 is moved according to the casting speed of the cast strand 7 by means of a torch control device 10 . Reference numeral 12 is a scale for measuring the weight of the cast slab 11 that has been cut.

In this embodiment, on the upstream side of the torch 9, a measuring device 13 for measuring the widthwise position of the short side surface 7a of the cast strand 7 is provided. As shown in FIG. 1, the measuring device 13 is arranged in the casting direction in the section from the last support roll 8a of the continuous casting installation 1 to the torch 9. As shown in FIG.

The measuring device 13 is a laser rangefinder. A laser rangefinder is a measuring instrument that measures the distance to an object by irradiating the surface of the object with laser light and receiving the reflected light. In particular, the measuring device 13 is a displacement sensor (two-dimensional laser displacement sensor) that irradiates the surface of an object with a laser beam that spreads like a band.

FIG. 2 is a schematic diagram for explaining the installation position of the measuring device. FIG. 3 is a schematic diagram for explaining a measuring method using a measuring device. When describing the arrangement and direction, the "width direction of the cast strand" may be simply referred to as the "width direction", and the "thickness direction of the cast strand" may be simply referred to as the "thickness direction".

As shown in FIG. 2, the measuring device 13 is arranged outside the short side surface 7a of the cast strand 7 in the width direction, and irradiates the short side surface 7a with a laser beam 14 that spreads in a belt shape in the thickness direction. do. This measuring device 13 measures the width direction position of the short side surface 7a by receiving the reflected light. For example, the measuring instrument 13 includes a light projecting section (not shown) that irradiates the short side surface 7a with the laser light 14 diffused in a band shape by a cylindrical lens, and a light receiving section (not shown) that receives the reflected light. ) and The measuring device 13 is provided with a light projecting portion and a light receiving portion arranged side by side in the casting direction. be. Further, in the thickness direction, as shown in FIG. 3, the position of the measuring device 13 (the position of the light receiving portion and the light projecting portion) is arranged at a position overlapping the thickness of the cast strand 7 . In the measuring device 13 arranged in this way, the light emitting part and the light receiving part are arranged at different positions in the casting direction, so that the laser light 14 diffused in a belt shape in the thickness direction is projected onto the short side surface 7a. It can be illuminated and its reflected light can be received.

As shown in FIG. 3, the measuring device 13 projects a laser beam 14 in the width direction, scans the short side surface 7a of the cast strand 7 over the entire thickness direction, and determines the width direction position of the short side surface 7a. Measure. Then, the distance L from the reference position to the short side surface 7a of the cast strand 7 is measured by the measuring device 13 in the width direction. This measurement range covers the entire thickness direction of the cast strand 7 . The distance L is the distance in the width direction, that is, the distance in the direction orthogonal to the thickness direction. Note that the reference position is indicated by a broken line in FIG.

For example, three points of the short side surface 7a, namely, the central portion in the thickness direction, the lower portion in the thickness direction, and the upper portion in the thickness direction will be described as an example. When short side bulging occurs in the cast strand 7, the distance L from the reference position to the thickness direction central portion of the short side surface 7a is the distance L from the reference position to the thickness direction upper portion and the thickness direction lower portion from the reference position. A measurement result is obtained that is shorter than the distance L to . In this way, the short side surface 7a of the cast strand 7 is scanned over the entire thickness direction by the belt-shaped laser beam 14, so that the measuring device 13 can cover the distance L, which is a measurement value, over the entire thickness direction. can.

Further, in this embodiment, the cross-sectional shape of the cast strand 7 is grasped by the measuring instrument 13 . In order to grasp the cross-sectional shape of the cast strand 7 during continuous casting, it is necessary to measure the width direction positions of the short side surfaces 7a on both sides of the cast strand 7 in the width direction. Therefore, in this embodiment, a pair of measuring instruments 13 are arranged on both sides of the cast strand 7 in the width direction. That is, the measuring device 13 includes a first measuring device arranged on one side in the width direction and a second measuring device arranged on the other side in the width direction. Both the first measuring device and the second measuring device are laser rangefinders. A pair of measuring instruments 13 arranged on both sides in the width direction of the cast strand 7 are arranged at the same position in the casting direction so as to measure the same part of the cast strand 7 in the casting direction. That is, the pair of measuring instruments 13 are configured to measure both sides of the cast strand 7 in the width direction at the same measurement timing at the same casting direction position in the section of the continuous casting facility 1 described above.

During continuous casting, the cast strand 7 passes in front of the measuring instrument 13 before being cut by the torch 9 . That is, the cast strand 7, which is a slab before cutting, passes through the area sandwiched by the pair of measuring instruments 13 in the width direction. During this passage, the distance L from the reference position to the short side surfaces 7a on both sides of the cast strand 7 is measured by the measuring device 13 over the entire thickness direction. Then, when the measuring device 13 measures the width direction position of the short side surface 7 a , this measured value is input from the measuring device 13 to the control device 15 . Note that the measuring device 13 may be installed on the pedestal 16 in order to adjust the position in the thickness direction.

The control device 15 is composed of an electronic control device and executes cutting control for controlling the cutting length of the cast slab 11 . The control device 15 includes the torch control device 10 .

The torch control device 10 calculates the representative cross-sectional area of the cast strand 7 using the measured value input from the measuring device 13, and determines the length of the cast slab 11 to be cut based on the calculated representative cross-sectional area. Execute control to decide. This torch control device 10 can cut the cast strand 7 according to the determined cutting length by controlling the torch 9 .

[Casting slab cutting length control method]
FIG. 4 is a flow chart showing an example of a cast slab cutting length control method. The processing shown in FIG. 4 is performed during continuous casting in the continuous casting facility 1. As shown in FIG.

During continuous casting, the measuring device 13 installed between the final support roll 8a and the torch 9 measures the width direction positions of the short side surfaces 7a on both sides of the cast strand 7 over the entire thickness direction. Measure (step S1). In step S1, the distance L from the reference position to the short side surface 7a is measured in the entire thickness direction of the cast strand 7. As shown in FIG. The measuring device 13 intermittently or continuously repeats this measurement. In other words, the measuring device 13 may perform measurements intermittently at predetermined measurement pitches, or may perform measurements continuously during continuous casting.

For example, for a slab cast at a casting speed of 1.8 m ² /min, when the above-described measurement is performed at intervals of 2 seconds, the profile in the thickness direction of the short side surfaces 7a on both sides of the cast strand 7 is 60 mm in the casting direction. You will get it on the pitch. That is, the temporal measurement pitch is 2 seconds, and the measurement pitch of the casting length to be measured is 60 mm.

The control device 15 calculates the representative cross-sectional area of the cast strand 7 using the measurement value measured by the process of step S1 and input from the measuring device 13 (step S2). In step S2, the cross-sectional shape of the cast strand 7 is drawn and the representative cross-sectional area of the cast strand 7 is calculated using the measured values input from the pair of measuring instruments 13 arranged on both sides in the width direction. In this case, measurement data (measurement values) measured by the measuring device 13 are collected. Then, in step S2, the cross-sectional area of the cast strand 7 is sequentially calculated as the casting progresses.

For example, as a method of calculating the cross-sectional area, first, the control device 15 performs a process of converting the widthwise position of the short side surface 7 a into a distance from the widthwise central position of the cast strand 7 . This widthwise center position is predetermined as the widthwise center position of the continuous casting facility 1 . Further, from the width direction position where the pair of measuring devices 13 are arranged, the width direction position of the measuring device 13 with respect to the width direction central position can be specified. Therefore, the control device 15 can calculate the distance from the center position in the width direction of the cast strand 7 to the position in the width direction of the short side surface 7 a based on the measured value by the measuring device 13 .

As a continuation of the method of calculating the cross-sectional area, the control device 15 executes a process of drawing the cross-sectional shape of the cast strand 7 on the virtual plane based on the measured values input from the measuring device 13 . In this case, the control device 15 connects the position corresponding to the upper end of one side and the position corresponding to the upper end of the other side of the short side surfaces 7a on both sides in the width direction with a straight line, and connects the position corresponding to the lower end of the one side with a straight line. A straight line connects the position corresponding to the lower end on the other side. Measured values are input to the control device 15 from the pair of measuring instruments 13 respectively. In addition, the control device 15 sets the line segment connecting the upper ends, the line segment connecting the lower ends, and the shape of the short side surfaces 7a on both sides in the width direction measured by the measuring device 13 so that the positions in the casting direction are the same. The cross-sectional shape of the cast strand 7 is drawn on the virtual plane of . This virtual plane is a two-dimensional plane in which one axis is the width direction of the cast strand 7 and the other axis is the thickness direction of the cast strand 7 . For example, the imaginary plane can set the center position in the width direction of the cast strand 7 as the origin of one axis (the axis corresponding to the width direction of the cast strand). In this way, the control device 15 can draw the cross-sectional shape of the cast strand 7 on the virtual plane based on the measured values input from the measuring device 13, calculate the length of the long side, and calculate the length of the short side. The shape can be determined by measurements from measuring instrument 13 .

As a further continuation of the cross-sectional area calculation method, the control device 15 determines the cross-sectional shape drawn on the virtual plane and the length of the long side of the calculated cross-sectional shape (a line segment connecting the upper ends in the width direction, A line segment connecting the lower ends in the width direction) and the measured thickness of the cast strand 7 (measured value by the measuring device 13), the process of calculating the cross-sectional area of the cross-sectional shape on the virtual plane is executed. . The thickness of the cross-sectional shape can be obtained from the measured value of the measuring device 13 . In this case, the control device 15 can use the measured value input from the measuring device 13 to calculate the representative cross-sectional area each time the measuring device 13 performs measurement. From the cross-sectional shape of the cast strand 7 thus obtained, the representative cross-sectional area of the cast strand 7 can be calculated. In the example in which the measuring device 13 measures at the above-described measuring pitch, the cross-sectional shape of the cast strand 7 is drawn every 60 mm in the casting direction.

The control device 15 integrates the representative cross-sectional areas calculated by the process of step S2 in the casting direction to determine the volume of the cast strand 7 (step S3). In step S3, the volume of the cast strand 7 is calculated over a predetermined length in the casting direction. The length in the casting direction for which the volume is calculated can be set to an appropriate length.

For example, when the cross-sectional shape of the cast strand 7 obtained for each measurement pitch described above is integrated in the casting direction, the control device 15 calculates the volume of the cast strand 7 downstream of the measurement position of the measuring device 13 in the casting direction can be obtained sequentially. In this manner, the volume and cross-sectional area can be calculated according to the length of the measurement period (the length of the cast strand 7 to be measured in the casting direction) performed by the measuring device 13 at predetermined intervals.

The control device 15 multiplies the volume calculated by the process of step S3 by the density of the slab considering the temperature of the slab to obtain the weight of the cast strand 7 downstream of the measurement position of the measuring device 13 (step S4). The slab temperature is the temperature of the cast strand 7 and is measured by a temperature sensor (not shown) provided in the continuous casting facility 1 . The slab temperature measured by this temperature sensor is input to the controller 15 . The slab density considering the slab temperature is a value determined for each steel type, and is stored in advance in the storage unit of the control device 15, for example. In step S4, the weight of the cast strand 7 is sequentially calculated as the casting progresses.

Alternatively, in step S4, the weight per unit length of the cast strand 7 can be obtained using the representative cross-sectional area of the cast strand 7 calculated by the process of step S2 and the specific gravity determined by the composition of the slab. . From the calculated weight per unit length and the length of the cast strand 7 downstream from the measurement position of the measuring device 13, the weight of the cast strand 7 downstream of the measuring position of the measuring device 13 is obtained. can be done. It should be noted that the specific gravity determined by the components of the slab is stored in advance in the storage unit of the control device 15, for example.

The control device 15 calculates the cut length of the cast slab 11 so that the weight of the cast strand 7 calculated by the process of step S4 corresponds to the required weight, and the calculated cut length is set to a predetermined length. is added to determine the cut length of the cast slab 11 (step S5). The required weight is the weight of the cast slab 11 required from the subsequent process of continuous casting (the process subsequent to the continuous casting process). In step S5, the weight of the cast strand 7 is first set so as to meet the required weight, and the length of the required weight is calculated as the cut length of the cast slab 11. FIG. That is, the control device 15 calculates the cut length by converting the weight into length. Then, by adding the length of the predetermined added weight (margin) to the cut length calculated to achieve the required weight, the length when the weight of the cast strand 7 is set to match the target weight is determined to be the cut length of the cast slab 11 . That is, in step S5, the control device 15 determines the cut length of the cast slab 11 so that the weight of the cast strand 7 matches the target weight obtained by adding a margin to the required weight. The margin is the weight (additional weight) added to the required weight when cutting the cast strand 7 to manufacture the cast slab 11 in the continuous casting process. The controller 15 determines the target length of the slab to be cut so as to match the target weight required in the subsequent process plus a margin. Therefore, in step S5, the controller 15 corrects the requested weight of the cast slab 11 by adding a margin, and determines the length of the cast slab 11 to be cut according to the corrected weight.

The control device 15 cuts the cast strand 7 according to the determined cutting length by controlling the torch 9 (step S6). In step S6, the torch control device 10 moves the torch 9 to a position in the casting direction where the volume of the cast strand 7 from the position measured by the measuring device 13 corresponds to the target weight, thereby cutting the cast slab 11. to control.

As described above, according to the embodiment, the width direction positions of the short side surfaces 7a on both sides of the cast strand 7 are measured by the measuring device 13 over the entire thickness direction, and the measured value is used as a representative section of the cast strand 7. The area can be calculated, and the cut length of the cast slab 11 to be cut can be determined from the representative cross-sectional area. As a result, even if the strand shape is not a perfect rectangular parallelepiped, an accurate cutting weight reflecting the shape of the cast strand 7 can be calculated, and as a result, the margin can be minimized. Further, by measuring the width direction positions of the short side surfaces 7a on both sides of the cast strand 7, the thickness of the cast strand 7 can be accurately grasped, so that the cutting weight can be calculated more accurately. . As a result, it becomes possible for the operator to operate without adding an excessive margin, and the yield is improved.

It should be noted that the present invention is not limited to the above-described embodiments, and can be modified as appropriate without departing from the scope of the present invention.

For example, in the above-described embodiment, the configuration in which the measuring device 13 performs measurements intermittently or continuously has been described, but the present invention is not limited to this. The measuring device 13 measures the widthwise position of the short side surface 7a at least once within the cutting interval until the cast slab 11 is cut by the torch 9 in the section from the final support roll 8a to the torch 9. can be configured as In short, it suffices that the measurement by the measuring device 13 is performed at least once in the above-described section in the casting direction from the previous cutting by the torch 9 to the next cutting. That is, the measurement by the measuring device 13 is performed at least once within the cutting interval of the processing (cutting step) of step S5 described above.

Moreover, the installation location of the measuring device 13 is not limited to the above-described embodiment. The installation location in the casting direction may be upstream of the torch 9 . In this case, the above-described secondary cooling zone is a measurement environment in which there are disturbances with respect to measurement by the measuring instrument 13, such as mist-like cooling water and water vapor evaporated by cooling. Therefore, it is preferable to install the measuring device 13 in the section between the final support roll 8a and the torch 9 as a measurement environment with little disturbance. Furthermore, when an optical sensor such as a laser range finder is used as the measuring device 13, a purge gas is provided in the gap between the casting strand 7 and the measuring device 13 so that the measurement light is not blocked by water vapor evaporated by cooling, dust, or the like. You may take measures such as distributing In addition, if the space between the cast strand 7 and the measuring instrument 13 cannot be sufficiently secured due to the lack of equipment space, etc., and there is a risk that the heat generated from the cast strand 7 will make the sensor unusable, the sensor Measures such as cooling and heat insulation may be taken.

Moreover, the measuring device 13 is not limited to the laser range finder described above. For example, the measuring device 13 may be an ultrasonic rangefinder or a contact rangefinder. Moreover, when the measuring device 13 is a laser rangefinder, the laser rangefinder is not limited to the two-dimensional laser displacement sensor described above. For example, the measuring device 13 may be a so-called one-dimensional laser displacement sensor that measures the distance to a point irradiated with linear laser light. In this case, by scanning the cast strand 7 in the thickness direction while synchronizing the sensor itself or the pedestal on which the sensor is installed with the movement of the cast strand 7 in the casting direction, the short side surfaces 7 a on both sides of the cast strand 7 , the width direction position of the short side surface 7a is measured over the entire thickness direction.

Further, the casting slab cutting length control method is not limited to a method including all of the steps S1 to S6 described above. For example, in the flowchart shown in FIG. 4, it is possible to proceed from the process of step S2 (cross-sectional area calculation step) to the process of step S4 (weight calculation step) without executing the process of step S3 (volume calculation step) described above. It is possible. In this case, in step S4, the weight per unit length of the cast strand 7 is calculated by multiplying the representative cross-sectional area of the cast strand 7 calculated in the process of step S2 by the specific gravity determined by the composition of the slab. Then, in step S5, the cut length is determined by dividing the required weight by the weight per unit length calculated in step S4. Thus, it is possible to determine the cut length of the cast slab 11 without calculating the volume of the cast strand 7 .

Further, it is possible to carry out a manufacturing method for manufacturing the cast slab 11 by cutting the continuously cast cast strand 7 so that the cut length is determined using the cast slab cutting length control method described above. is.

An example based on the above-described embodiment will now be described. In the embodiment, at the timing of casting carbon steel with a strand width of 1400 mm and a thickness of 220 mm, the short side shape is measured by the measuring device 13, which is a laser rangefinder, and the cross-sectional area of the cast strand 7 obtained from the measurement result is Calculation of the cross-sectional area (assuming a rectangle) was compared. In the conventional method, the cross-sectional area was calculated as a rectangular cross section with a width of 1.424 m and a thickness of 0.22 m. On the other hand, in the method of Example, when the area of the portion where the short side was bulging was obtained, the area was 0.00152 m ² . That is, while the cross-sectional area calculated by the conventional method is (1.424 × 0.22) m ² , in the method of the example, a value of the cross-sectional area that is closer to the actual situation is (1.424 × 0 .22+0.00152) m ² is obtained. At this casting timing, the ^average cut length was 3.243 m. .22 x 7.85 = 7.96 tons, while in the method of the embodiment, 3.243 x (0.22 x 1.424 + 0.00152) x 7.85 = 8.01 tons. In other words, in the conventional method, the operation was sometimes performed based on an estimate of about 50 kg less than the actual amount per slab. Presumably it was set. Thus, according to the embodiment, it is possible to calculate the cutting weight more accurately than the conventional method, so that the operator can operate without adding an excessive margin, and the yield is improved. improvement can be realized.

REFERENCE SIGNS LIST 1 continuous casting equipment 2 ladle 3 refractory nozzle 4 tundish 5 immersion nozzle 6 mold 7 casting strand 7a short side 8 support roll 8a final support roll 9 torch (cutting device)
REFERENCE SIGNS LIST 10 torch control device 11 casting slab 12 scale 13 measuring device 14 laser light 15 control device 16 pedestal L distance

Claims (12)

A casting slab cutting length control method for obtaining a casting slab of a target length by cutting a continuously cast casting strand, comprising:
A measuring step, which is performed at predetermined intervals for the short side surfaces on both sides in the width direction of the cast strand, in which the width direction positions of the short side surfaces are scanned and measured over the entire thickness direction of the cast strand;
Cross-sectional area calculation for calculating a representative cross-sectional area of the cast strand according to the length of the measurement period performed at each of the predetermined intervals at each of the measuring steps, using the measured values obtained in the measuring step a step;
a determination step of determining the cut length of the cast slab to be cut using the volume of the cast strand obtained by integrating the representative cross-sectional area of the cast strand calculated in the cross-sectional area calculation step in the casting direction;
a cutting step of cutting the cast slab to a cutting length determined by the determining step;
including
the measurement of the measuring step is performed at least once within the cutting interval of the cutting step ;
Further comprising a weight calculation step of calculating the weight per unit length of the cast strand using the representative cross-sectional area of the cast strand calculated by the cross-sectional area calculation step,
The determining step includes determining a cut length of the cast slab to be cut using the weight calculated by the weight calculating step.
A casting slab cutting length control method characterized by: A casting slab cutting length control method for obtaining a casting slab of a target length by cutting a continuously cast casting strand, comprising:
A measuring step of measuring the width direction positions of the short side surfaces on both width direction sides of the cast strand in the thickness direction of the cast strand;
A cross-sectional area calculation step of sequentially calculating the cross-sectional area of the cast strand as casting progresses, using the measured values measured in the measuring step;
A volume calculation step of calculating the volume of the cast strand by integrating the cross-sectional areas of the cast strand sequentially calculated by the cross-sectional area calculation step in the casting direction;
a determination step of determining a cut length of the cast slab to be cut using the volume of the cast strand calculated by the volume calculation step;
a cutting step of cutting the cast slab to a cutting length determined by the determining step;
including
The measurement in the measuring step is performed intermittently or continuously within the cutting interval of the cutting step ,
A weight calculation step of calculating the weight of the cast strand using the volume of the cast strand calculated by the volume calculation step,
The determining step includes determining a cut length of the cast slab to be cut using the weight calculated by the weight calculating step.
A casting slab cutting length control method characterized by: 3. The casting slab according to claim 1 or 2 , wherein in the determining step, the required casting slab weight is corrected by adding a margin to determine the cut length of the casting slab to be cut. Cutting length control method. Cutting the cast slab according to any one of claims 1 to 3 , characterized in that the measurement in the measuring step is performed in the casting direction section from the last support roll to the cutting device of the continuous casting facility. Length control method. 5. The measuring step according to any one of claims 1 to 4 , wherein the measuring step includes a step of measuring the width direction position of the short side face in the thickness direction of the cast strand with a laser rangefinder. Cutting length control method for casting slabs. A casting slab cutting length control device for cutting a continuously cast casting strand to obtain a casting slab of a target length, comprising:
a measuring device that is performed at predetermined intervals for the short side surfaces on both sides in the width direction of the cast strand and scans and measures the width direction positions of the short side surfaces over the entire thickness direction of the cast strand;
Using the measured value measured by the measuring device, a representative cross-sectional area of the cast strand is calculated according to the length of the measurement period performed at each predetermined interval at each measurement with the measuring device. cross-sectional area calculation means;
determining means for determining the cut length of the cast slab to be cut using the volume of the cast strand obtained by integrating the representative cross-sectional area of the cast strand calculated by the cross-sectional area calculating means in the casting direction;
a cutting device for cutting the cast slab to the cutting length determined by the determining means;
with
The measuring device measures the width direction position of the short side surface at least once within the cutting interval by the cutting device ,
weight calculation means for calculating the weight per unit length of the cast strand using the representative cross-sectional area of the cast strand calculated by the cross-sectional area calculation means;
The determining means uses the weight calculated by the weight calculating means to determine the cutting length of the cast slab to be cut.
A casting slab cutting length control device characterized by: A casting slab cutting length control device for cutting a continuously cast casting strand to obtain a casting slab of a target length, comprising:
a measuring device for measuring the width direction positions of the short side surfaces on both width direction sides of the cast strand in the thickness direction of the cast strand;
Cross-sectional area calculation means for sequentially calculating the cross-sectional area of the cast strand as casting progresses, using the measured values measured by the measuring device;
A volume calculation means for calculating the volume of the cast strand by integrating the cross-sectional areas of the cast strand sequentially calculated by the cross-sectional area calculation means in the casting direction;
a determination means for determining a cut length of the cast slab to be cut using the volume of the cast strand calculated by the volume calculation means;
a cutting device for cutting the cast slab to the cutting length determined by the determining means;
with
The measuring device intermittently or continuously measures the width direction position of the short side surface within the cutting interval by the cutting device ,
weight calculation means for calculating the weight of the cast strand using the volume of the cast strand calculated by the volume calculation means;
The determining means uses the weight calculated by the weight calculating means to determine the cutting length of the cast slab to be cut.
A casting slab cutting length control device characterized by: 8. The cast slab according to claim 6 or 7 , wherein the determining means performs a correction to add a margin to the requested cast slab weight to determine the cut length of the cast slab to be cut. Cutting length controller. The casting slab cutting according to any one of claims 6 to 8 , wherein the measuring device performs the measurement in a casting direction section from the last support roll of the continuous casting facility to the cutting device. Length controller. 10. The casting slab cutting length control apparatus according to any one of claims 6 to 9 , wherein the measuring device is a laser rangefinder. A cast slab manufacturing method for manufacturing a cast slab having a target length by cutting a continuously cast cast strand,
A measuring step, which is performed at predetermined intervals for the short side surfaces on both sides in the width direction of the cast strand, in which the width direction positions of the short side surfaces are scanned and measured over the entire thickness direction of the cast strand;
Cross-sectional area calculation for calculating a representative cross-sectional area of the cast strand according to the length of the measurement period performed at each of the predetermined intervals at each of the measuring steps, using the measured values obtained in the measuring step a step;
a determination step of determining the cut length of the cast slab to be cut using the volume of the cast strand obtained by integrating the representative cross-sectional area of the cast strand calculated in the cross-sectional area calculation step in the casting direction;
a cutting step of cutting the cast slab to a cutting length determined by the determining step;
including
the measurement of the measuring step is performed at least once within the cutting interval of the cutting step ;
Further comprising a weight calculation step of calculating the weight per unit length of the cast strand using the representative cross-sectional area of the cast strand calculated by the cross-sectional area calculation step,
The determining step includes determining a cut length of the cast slab to be cut using the weight calculated by the weight calculating step.
A casting slab manufacturing method characterized by: A cast slab manufacturing method for manufacturing a cast slab having a target length by cutting a continuously cast cast strand,
A measuring step of measuring the width direction positions of the short side surfaces on both width direction sides of the cast strand in the thickness direction of the cast strand;
A cross-sectional area calculation step of sequentially calculating the cross-sectional area of the cast strand as casting progresses, using the measured values measured in the measuring step;
A volume calculation step of calculating the volume of the cast strand by integrating the cross-sectional areas of the cast strand sequentially calculated by the cross-sectional area calculation step in the casting direction;
a determination step of determining a cut length of the cast slab to be cut using the volume of the cast strand calculated by the volume calculation step;
a cutting step of cutting the cast slab to a cutting length determined by the determining step;
including
The measurement in the measuring step is performed intermittently or continuously within the cutting interval of the cutting step ,
A weight calculation step of calculating the weight of the cast strand using the volume of the cast strand calculated by the volume calculation step,
The determining step includes determining a cut length of the cast slab to be cut using the weight calculated by the weight calculating step.
A casting slab manufacturing method characterized by:

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