JP5587825B2 - Tension control device and control method for hot rolling mill - Google Patents

Description

  The present invention relates to a tension control device for a hot rolling mill and a control method therefor, and in particular, heat control suitable for stabilizing steel sheet tension control between stands and reducing steel sheet quality defects such as sheet thickness fluctuation and width shrinkage. The present invention relates to a tension control device and a control method for a rolling mill.

  As a conventional technique for controlling the steel plate tension between the stands of the hot rolling mill by paying attention to the plate width and plate thickness accuracy of the steel plate, there has been the following method.

  Patent Document 1 describes a method of measuring the actual value of the plate width from a plate width meter provided on the finish stand exit side, and correcting the tension setting value so that this becomes the plate width target value.

  Patent Document 2 describes an evaluation function based on a time series of measured values of sheet thickness, sheet width and sheet temperature on the finish stand exit side, a time series of target sheet thickness and target sheet width, and a dynamic model of finish rolling. A control method for optimally setting rolling conditions (setting of rolling stand load, setting of tension between rolling stands, etc.) during finish rolling is shown.

  In addition, in Patent Document 3, in the hot reciprocating rolling mill, the tension command value at both ends of the steel plate is set high, and the tension command value is set low at the portion excluding both ends, thereby suppressing the width shrinkage of the steel plate. The control method is shown.

JP 2000-312909 A JP-A-9-122723 JP 2009-279638 A

  In general, the effect of the tension of a steel plate on the plate width and thickness varies depending on the temperature of the steel plate. However, the above-described conventional method has the following problems in addition to insufficient consideration for this point.

  In order to improve the width accuracy with high response, it is better to change the tension between the downstream stands. On the other hand, the effect that the change in tension changes the plate width is greater when the steel plate is thicker.

  In this regard, if the tension between the downstream stands is manipulated with the technique of Patent Document 1 in order to increase the width control, the plate thickness is already thin at the downstream stand. It was necessary to change greatly, and there was a possibility of impairing rolling stability. Conversely, when the width is controlled by changing the tension between the upstream stands, efficient plate width control is possible, but it takes a long time for the control result to appear on the plate width meter. There was a problem that the response of control became slow.

  The method described in Patent Document 2 is a method of determining a control command value according to a complex calculation of multiple inputs using an evaluation function, although there is a possibility that the accuracy of the plate width and thickness can be improved comprehensively. Therefore, many parameter adjustments are necessary to obtain the best results. Therefore, there is a fear that a great deal of labor is required for the construction and maintenance of the control system.

  The method described in Patent Document 3 is aimed at obtaining a uniform plate width by changing the set value of tension control by paying attention to the position of the steel plate, but with respect to various temperature changes of the steel plate. The tension change to compensate for this is only shown to be tapered. Therefore, the influence of the change in tension on the change in the plate width is not sufficiently considered. For this reason, the plate width may fluctuate between the front and rear ends of the steel plate and other portions.

  Therefore, the problem to be solved by the present invention is to obtain a uniform plate width in the longitudinal direction of the steel plate by a simple method using temperature information of the steel plate.

  In the present invention, in order to solve the above-described problem, a tension control device for a hot rolling mill that includes a plurality of rolling stands and is applied to at least two sets of adjacent rolling stands as one set, The rolling stand includes a looper between the upstream rolling stand and the downstream rolling stand, and each set of rolling stands in a tension control device of a hot rolling mill that controls the tension of the steel plate between the rolling stands to a desired value. The tension command storing means for storing the tension command value and the tension command correcting means for taking in the detected temperature from the thermometer for measuring the temperature of the steel sheet and correcting the tension command value according to the deviation between the target temperature and the detected temperature of the steel sheet The tension control means adjusts each set of rolling stands according to the deviation between the corrected tension command value and the detected tension value.

  Further, when the detected temperature of the steel plate becomes higher than the target temperature, the weakening tension control is performed, and when the detected temperature of the steel plate is lower than the target temperature, the strong tension control is performed.

  Also, the detected temperature of the hot rolling mill outlet thermometer provided on the outlet side of the hot rolling mill is taken in, and the tension command value is corrected according to the deviation between the target temperature on the outlet side of the hot rolling mill and the detected temperature. Tension command correction means was provided.

  Also, the detected temperature of the hot rolling mill inlet side thermometer provided on the inlet side of the hot rolling mill is taken in, and the tension command value is corrected according to the deviation between the target temperature on the inlet side of the hot rolling mill and the detected temperature. Tension command correction means was provided.

  Moreover, from the 1st detected temperature detected from the hot rolling mill entrance thermometer with which the hot rolling mill was provided, and the hot rolling mill exit thermometer with which the hot rolling mill was provided The detected second detected temperature is taken in, the deviation between the target temperature on the hot rolling mill inlet side and the first detected temperature is calculated as the first temperature deviation, and the target temperature on the hot rolling mill outlet side and the second The detected temperature deviation is calculated as a second temperature deviation, and the tension command correction means obtains a correction signal by the sum of the first temperature deviation and the second temperature deviation.

  For a plurality of rolling stands, the control gain of the tension command correction means for the upstream rolling stand set is set to be larger than the control gain of the tension command correction means for the downstream rolling stand set.

  In the present invention, in order to solve the above-mentioned problem, a plurality of rolling stands are provided, and the adjacent rolling stands are applied to at least two sets as one set, and each set of rolling stands includes an upstream side rolling stand and a downstream side rolling stand. In a tension control method of a hot rolling mill that includes a looper between the rolling stands and controls the tension of the steel plate passing through the rolling stand to a desired value, the temperature of the steel plate is detected, and between the rolling stands, When the detected temperature becomes higher than the target temperature, the weaker tension control is performed, and when the detected temperature of the steel sheet is lower than the target temperature, the stronger tension control is performed.

  Further, the temperature of the steel sheet is the temperature on the downstream side of the hot rolling mill.

  Further, the temperature of the steel sheet is the temperature on the upstream side of the hot rolling mill.

  The temperature of the steel sheet is the temperature on the entry side and the temperature on the exit side of the hot rolling mill, and the weak tension control or the strong tension control is performed according to the sum of the temperature deviations from the respective target temperatures.

  In the present invention, in order to solve the above-mentioned problem, a plurality of rolling stands are provided, and the adjacent rolling stands are applied to at least two sets as one set, and each set of rolling stands includes an upstream side rolling stand and a downstream side rolling stand. In the tension control method of a hot rolling mill that includes a looper between the rolling stand and controls the tension of the steel plate that passes through the rolling stand to a desired value, the temperature of the steel plate is detected, and the temperature deviation from the target temperature, When the detected temperature becomes higher than the target temperature, the weaker tension control is performed. When the detected temperature falls below the target temperature, the stronger tension control is performed, and the control gain for the temperature deviation with respect to the upstream set of rolling stands is set downstream. A large control gain is set for the temperature deviation between the rolling stands of the side set.

  The tension command correction means compensates for the influence of fluctuations in the steel plate temperature during rolling on the plate thickness and plate width using the tension between the stands as the operation end. As a result, a uniform plate width and plate thickness can be obtained in the longitudinal direction of the steel plate. Moreover, highly responsive tension control is realizable by correct | amending the tension between stands using the steel plate temperature measured with the thermometer with which the entrance side or exit side of the hot rolling mill was equipped.

The figure which showed the 1st Example of the tension control apparatus of a hot rolling mill. The figure which shows the structure of the tension command storage means 151. FIG. The figure which shows the process of the load torque estimation means 155. FIG. Explanatory drawing of the model which estimates load torque. The figure which shows the structure of the looper height instruction | command production | generation means 156. FIG. The figure which shows the process of the looper support torque estimation means 158. FIG. Explanatory drawing of the model which estimates a looper support torque. The figure which shows the process of the tension command correction means 171. The figure which showed the 2nd Example of the tension control apparatus of a hot rolling mill. The figure which shows the process of the tension | tensile_strength instruction | command correction means 901. FIG. The figure which showed the 3rd Example of the tension control apparatus of a hot rolling mill. The figure which shows the process of the tension | tensile_strength instruction | command correction means 1101. FIG. The figure which showed the 4th Example of the tension control apparatus of a hot rolling mill.

  Embodiments of the present invention will be described below with reference to the drawings. In the tension control of the hot rolling mill of the present invention, simply speaking, the temperature of the steel sheet of the hot rolling mill is measured, the target value of the tension control is corrected by the steel plate temperature, and the operation end of the hot rolling mill is driven. . In each embodiment, the measurement point of the steel plate temperature or the operation end is specifically specified. In addition, the relationship between the temperature and tension of the steel sheet is clarified.

  According to the present invention, it is possible to stabilize the tension control in the finishing stand, to improve the stability during rolling and to improve the sheet passing property, and it is possible to obtain a steel plate having a highly accurate plate width and thickness.

  FIG. 1 shows a first embodiment of the present invention. The tension control of the hot rolling mill according to the first embodiment is characterized in that correction based on the hot rolling mill outlet temperature is performed and the stand drive device is driven. In FIG. 1, the tension control device 15 receives various signals from the control target 10 (hot rolling mill) and outputs control signals to the control target 10.

  First, the configuration of the controlled object 10 will be described. In this embodiment, the controlled object 10 is a tandem mill in which a steel plate 103 is continuously rolled by a plurality of stands 101. The steel plate 103 moves from the left to the right in the drawing, and the steel plate 103 is gradually rolled thinly as it proceeds from the first stand 101F on the upstream side to the second stand 101B on the downstream side. Note that there are actually a plurality of stands on the upstream side, and about 6 to 7 stands are often arranged in a normal finishing mill. FIG. 1 shows only two of them adjacent to each other.

  FIG. 1 shows an example of a four-stage mill in which the stand 101 includes a work roll 104 that actually rolls a plate and a backup roll 105 that supports the stand, with a steel plate 103 interposed therebetween. The drive device 109 drives the work roll 104. Although omitted in the figure, a drive device for driving the backup roll is also provided.

  The steel plate 103 between the stands 101F and 101B generates a tension that is a force for pulling the steel plate in the longitudinal direction. For each stand 101, the steel sheet tension on the entry side is referred to as rear tension, and the steel sheet tension on the exit side is referred to as front tension. In the example of the stand 101F, the rear tension is Tb and the front tension is Tf.

  The looper 11 provided between the stands 101F and 101B includes a looper cylinder 111, a looper arm 112, and the like, and plays a role of stabilizing the threading plate and tension by supporting the steel plate 103. The height of the looper 11 is controlled by the looper driving device 108, and the looper height is detected by a height meter 114. Further, the tension of the steel plate 103 between the stand 101F and the stand 101B (the front tension Tf when viewed from the stand 101F) can be measured by a tension meter 113 attached to the looper arm 112. A looper is usually installed between each stand.

  As is apparent from this figure and the above description, the operation ends in the hot rolling mill of the present invention are a drive device 109 and a looper drive device 108.

  Next, a basic configuration of the tension control device 15 which is a premise of the present invention will be described with reference to FIGS. As described above, in the tension control of the hot rolling mill according to the first embodiment, the hot rolling mill outlet side temperature is corrected, and the drive device 109 of the stand 101F is driven as the operation end. There is. This characteristic part will be described with reference to FIG.

  Various methods such as a method using optimum control are known as tension control. In this embodiment, a method of estimating the load torque and performing feedforward control will be described as an example. First, the overall configuration will be briefly described, and then the operation of each unit will be described in detail.

  The tension control device 15 performs tension control of the controlled object 10 in which a plurality of rolling equipments each having a set of front and rear stands and loopers are arranged. Here, a control circuit that performs tension control of a set of front and rear stands and loopers. The part is illustrated. That is, in the tension control device 15 of FIG. 1, a pair of front and rear stands and a looper are, for example, the stands 101F and 101B and the looper 110, and a control circuit portion that performs this tension control is the interstand tension control means 155.

  Therefore, the inter-stand tension control means is also provided for the stand 101B, the subsequent stand, and its looper. Similarly, an inter-stand tension control means 155 is also provided for the stand 101F, its preceding stage stand, and its looper. As described above, the entire control target 10 includes a plurality of stands, and when the adjacent stands are set as one set, at least two sets or more are provided with the inter-stand tension control means 155. These inter-stand tension control means 155 have the same function with the front and rear stands and the looper as a set of operation targets.

  The inter-stand tension control means 155 in the tension control device 15 receives actual data such as rolling load P, tension Tf, Tb, looper height θ, steel plate speed, etc. of each stand from the control object 10 via the actual result collecting means 16. Capture. Further, the operation signals id and il are given from the inter-stand tension control means 155 of the tension control device 15 to the stand 101F and the looper 11 which are the operation targets.

  A drive device 109 that is an operation end that drives the work roll 104 of the stand 101 that is one operation target is controlled in accordance with a tension command Tfs. That is, the tension control means 152 operates so that the actual value Tf of the front tension matches the tension command Tfs. Thereafter, the speed control means 154 performs speed control calculation of the drive device 109, finally calculates a current command id for driving the drive device 109, and outputs it to the drive device 109. The load torque estimating means 155 is a feedforward compensator for performing non-interference with the looper control system.

  The looper driving device 108 that operates the looper 110 that is the other operation target is controlled according to the looper height command θs. That is, the looper height control means 157 operates so that the actual value θ of the looper height coincides with the looper height command value θs, finally calculates the current command il for driving the looper driving device 108, and drives the looper. Output to the device 108. Looper support torque estimating means 158 is a feedforward compensator for performing non-interference with the tension control system. Thus, in this embodiment, the tension is controlled by the drive speed, and the looper height is controlled by the looper height control.

Next, the operation of each unit will be described in detail. FIG. 2 shows the configuration of the tension command storage means 151. In the illustrated example, the tension command of the steel plate 103 between the stands is stratified by the steel type, the plate thickness, and the plate width. For example, when the steel type is SS400, the plate thickness is 2.0 to 3.0 mm, and the plate width is 900 mm, it is 1.5 kg / mm ² . Here, since the plate | board thickness between each stand is uniquely determined by a rolling schedule, tension | tensile_strength setting value can be determined from the steel grade and plate | board thickness determined after that. In addition to the example of FIG. 2, it is also possible to add and determine the moving speed of the steel sheet 103 or a stand as the stratification condition.

The tension set value determined in this way is set as a front tension command value Tfs, and the tension control means 152 inputs a difference ΔTf between this value and the detected front tension detection value Tf, and becomes an input to the speed control means 154. A speed set value Vs is calculated. The speed set value Vs can be calculated by, for example, a proportional integration calculation represented by the equation (1). In equation (1), K1 is a proportional gain, T1 is an integration time, and S is a Laplace operator.
[Equation 1]
Vs = K1 (1 + 1 / T1S) ΔTf (1)
Thereafter, a speed tuning process called “successive” is performed. That is, when the work roll gap or the work roll speed changes in the downstream stand 101B, the corresponding speed change amount ΔV2 is compensated in the upstream stand 101F. The speed change amount ΔV2 to be compensated is obtained by, for example, equation (2). However, in the formula (2), b is the reverse rate of the downstream stand 101B, f is the advance rate of the upstream stand 101F, and ΔV1 is the speed change amount of the downstream stand.
[Equation 2]
ΔV2 = (1−b) / (1 + f) ΔV1 (2)
The speed control means 154 calculates a current command (torque command) C1 for driving the drive device 109 from Vs + ΔV2. C1 is calculated by, for example, equation (3). Equation (3) is an example in which the speed control means 154 is realized by proportional-integral control, where K2 is a proportional gain, T2 is an integration time, C1n is a current value of C1, and V is an actual value of speed. ΔV is obtained as ΔV = Vs + ΔV2−V.
[Equation 3]
C1 = C1n + K2 (1 + 1 / T2S) ΔV (3)
FIG. 3 shows a process executed by the load torque estimating unit 155. The load torque estimating means 155 takes in the front tension Tf, the rear tension Tb, and the rolling load P from the result collecting means 16 in step S31. In step S32, a value E1 corresponding to the load torque out of the total torque of the drive device 109 is estimated as follows.

FIG. 4 shows an example in which the steel plate 103 is rolled by the work roll 104. The steel plate 103 proceeds from left to right, P is a rolling load, and P (x) is a rolling load per unit length of the steel plate 103 at the part x. When the rolling load P (x) per unit length is integrated for the part x, it coincides with P which is the total amount of the load. R is the radius of the work roll 104. At this time, it is known that the load torque E1 can be calculated by the equation (4). However, R1 is a flat roll diameter.
[Equation 4]
E1 = (R / R1) ∫Pxdx + (R / 2) (Tb−Tf) (4)
The load torque estimation means 155 estimates the load torque E1 by calculating equation (4). Finally, a value obtained by adding E1 and C1 is output to the drive device 109 as a current command id.

  Next, obtaining another operation signal (current command signal il) will be described. Here, the looper height is controlled, and the looper height command θs as the target signal is obtained by the looper height command generation means 156. The looper height command generation means 156, an example of which is shown in FIG. 5, includes a looper height command storage means 502 that stores a looper height command θs corresponding to the passage length L of the steel plate 103, and a looper height command storage. Looper height command determining means 501 for determining and outputting the looper height based on the information stored in the means 502 is provided.

  In the looper height command storage means 502, three types of looper heights are set corresponding to the passage length L of the steel plate 103 as shown in FIG. The first looper height is the looper height command 503 for the length of the looper height that rises with respect to the tip of the steel plate 103 and comes into contact with the steel plate 103, and the second looper height is determined by the looper 11 being the steel plate The steady looper height command 504 and the third looper height when supporting and passing the plate 103 reduce the looper height near the tail end of the steel plate 103 and eliminate the contact between the looper 11 and the steel plate 103. Is the height command 505 at the time.

  These are stored corresponding to the passage length L of the steel plate 103. Here, the passage length signal L is a distance from the front end of the steel plate at a portion of the steel plate 103 supported by the looper 11. Therefore, the looper height command changes as the steel plate 103 passes.

  The looper height determination means 501 takes the passage length signal L of the steel plate 103 from the result collection means 16 and extracts the looper height command θs with reference to the looper height command storage means 502. The extracted θs is output as a looper height command.

The looper height control means 157 receives a difference Δθ between the looper height command value θs and the looper height detection value θ. The looper height control means 157 calculates a current command (torque command) C2 for driving the looper driving device 108 from Δθ. C2 is calculated by, for example, equation (5). Equation (5) is an example in which looper height control is realized by proportional / integral control, where K3 is a proportional gain and T3 is an integration time.
[Equation 5]
C2 = K3 (1 + 1 / T3S) Δθ (5)
FIG. 6 shows the processing of the looper support torque estimating means 158. The looper support torque estimating means 158 takes in the front tension Tf and the looper height θ from the result collecting means 16 in step S61. In step S62, a value E2 corresponding to the load torque for supporting the looper out of the total torque of the looper driving device 108 is estimated as follows.

FIG. 7 shows an example in which the steel plate 103 rolled by the stand 101F and the stand 101B is supported by the looper arm 112. The steel plate 103 progresses from left to right, La is the length of the looper arm 112, θ is the looper height (looper angle), and β is the angle of the steel plate 103 with respect to the horizontal position.
At this time, it is known that the looper support torque E2 can be calculated by the equation (6). Here, D is a velocity friction coefficient with respect to a change in the angle of the looper.
[Equation 6]
E2 = K1 (θ) Tf + K2 (θ) + K3 (θ) + D (dθ / dt) (6)
The coefficient K1 (θ) in the equation (6) can be expressed by the equation (7) using the plate thickness h and the plate width b.
[Equation 7]
K1 (θ) = 2hbLa · conθsinβ (7)
The coefficient K2 (θ) in the equation (6) can be expressed by the equation (8) using the specific gravity ρ of the steel plate 103.
[Equation 8]
K2 (θ) = 2ρhbg · (l / conβ) La · cos θ (8)
Furthermore, the coefficient K3 (θ) in equation (6) can be expressed by equation (9).
[Equation 9]
K3 (θ) = Wlgrl · cos θ (9)
Here, Wl is the weight of the looper arm 112, g is gravitational acceleration, and rl is the distance from the fulcrum of the looper arm 112 to the position of the center of gravity.

  The coefficients in the equations (7) to (9) are all functions of the looper angle θ, and the value of the support torque changes. The physical meaning of these coefficients is that K1 (θ) is a support torque generated by tension, K2 (θ) is a support torque generated by supporting the weight of the steel plate 103, and K3 (θ) is a weight of the looper arm 112. This is the generated support torque.

  Finally, using the estimated E2, a value obtained by adding E2 and C2 is output to the looper driving device 108 as a current command il.

  With the above calculation, the drive device 109 and the looper drive device 108 operate in conjunction with each other with the interference of the steel plate 103 eliminated.

The present invention is applied on the premise of the configuration described above, and FIG. 8 shows the processing of the tension command correcting means 171 realized in the first embodiment of the present invention. In this tension command correction means 171, first, in step S 81, the hot rolling mill outlet temperature target value Mfs is fetched from the hot rolling mill outlet temperature target value storage section 170 of FIG. Further, in step S82, the actual value Mf of the hot rolling mill outlet temperature is fetched from the hot rolling mill outlet thermometer 130 of FIG. Then, the difference ΔFDT between them is calculated by the equation (10). ΔFDT takes a positive value when the actual temperature value is high.
[Equation 10]
ΔFDT = Mfs−Mf (10)
Next, in step S83, the tension command correction value ΔTf1 is calculated by the equation (11) and output. However, in the equation (11), Kt1 is a proportional gain.
[Equation 11]
ΔTf1 = Kt1 · ΔFDT (11)
The tension command correction value ΔTf1 obtained by the proportional calculation process in this way becomes a larger value as the actual value of the hot rolling mill delivery side temperature is larger than the target value, and conversely a smaller value. The smaller the value.

  Further, as shown in FIG. 1, the tension command correction value ΔTf1 output from the tension command correction unit 151 is subtracted from the tension command Tfs output from the tension command storage unit 151, and (Tfs−ΔTf1) becomes a new tension. It becomes a command value.

  This is because, according to the first embodiment of the present invention, the target tension of the tension control means 152 decreases as the actual value Mf of the hot rolling mill outlet temperature exceeds the target value Mfs. It means to become. That is, at this time, weakening tension control is performed.

  Similarly, it means that as the actual value Mf of the hot rolling mill outlet side temperature exceeds the target value Mfs and becomes lower, the target tension of the tension control means 152 is increased. That is, at this time, a stronger tension control is performed.

  In addition, when a plurality of stands are installed, the proportional gain Kt1 may be the same between the upstream stands and between the downstream stands. However, since the tension correction effect is greater between the upstream stands, It is better to make the distance between the stands slightly larger.

  In the first embodiment, one stand and a looper have been described as an example. However, in a tandem mill in which the stands are continuous in multiple stages, the same processing can be realized by preparing the same for each stand and looper.

  According to the first embodiment in which tension control is performed at the rolling mill outlet side temperature Mf, temperature changes such as when water is injected between the stands can be quickly reflected in the control.

  In FIG. 1, a hot rolling mill outlet thermometer 130 is an existing thermometer used in many cases for other purposes for controlling the rolling mill or for managing the quality of the steel sheet. The invention uses this signal for tension control. Moreover, the hot rolling mill outlet side thermometer 130 is installed on the outlet side of the last stage stand of the plurality of stands.

  FIG. 9 shows a second embodiment of the present invention. In FIG. 9, the correction value of the tension command is calculated using the rolling mill entrance side temperature Mb instead of the rolling mill exit side temperature Mf, and the drive device is driven as the operation end. The configuration and functions of FIG. 9 are the same as those of FIG. 1 except for this point.

  FIG. 10 shows processing performed by the tension command correction unit 901. First, in step S101, the tension command correction unit 901 takes in the target value Mb of the hot rolling mill inlet side temperature from the hot rolling mill inlet side temperature target value storage unit 903. The target value Mbs of the hot rolling mill entry side temperature may be constant, but may be a different value according to the part of the steel sheet.

Further, in step S102, the actual value Mb of the hot rolling mill inlet side temperature is taken from the hot rolling mill inlet side thermometer 902, and the difference ΔFET between them is calculated by the equation (12). ΔFET takes a positive value when the actual temperature value is high.
[Equation 12]
ΔFET = Mbs−Mb (12)
In step S103, the tension command correction value ΔTf1 is calculated by the equation (13) and output. Here, Kt2 is a proportional gain.

[Equation 13]
ΔTf1 = Kt2 · ΔFET (13)
Thus, the tension command correction value ΔTf1 obtained by the proportional calculation process becomes larger as the actual value Mb of the hot rolling mill entry side temperature is larger than the target value Mbs, and conversely, a smaller value. The smaller the value, the smaller the value.

  As shown in FIG. 1, the tension command correction value ΔTf1 output from the tension command correction unit 901 is subtracted from the tension command Tfs output from the tension command storage unit 151, and (Tfs−ΔTf1) becomes a new tension. It becomes a command value.

  This also results in lowering the target tension of the tension control means 152 as the actual value Mb of the hot rolling mill entry side temperature exceeds the target value Mbs in the second embodiment of the present invention. Means. That is, at this time, weakening tension control is performed.

  Similarly, it means that as the actual value Mb of the hot rolling mill entry side temperature exceeds the target value Mbs and becomes lower, the target tension of the tension control means 152 is increased. That is, at this time, a stronger tension control is performed.

  In addition, when a plurality of stands are installed, the proportional gain Kt1 may be the same between the upstream stands and between the downstream stands. However, since the tension correction effect is greater between the upstream stands, It is better to make the distance between the stands slightly larger.

  In this embodiment, a pair of front and rear stands and a looper have been described as an example. However, in a tandem mill in which the stands are continuous in multiple stages, the same processing can be realized by preparing the same for each stand and looper.

  According to the second embodiment in which the tension is controlled by the rolling mill entry side temperature Mb, a high speed response can be expected because the control is performed by the temperature change on the upstream side.

  In FIG. 1, a hot rolling mill entry-side thermometer 902 is an existing thermometer used for other purposes for controlling the rolling mill in many cases and for managing the quality of the steel sheet. The invention uses this signal for tension control. Moreover, the hot rolling mill outlet-side thermometer 902 is installed on the entry side of the foremost stand of the plurality of stands.

  FIG. 11 shows a third embodiment of the present invention. In FIG. 11, the correction value of the tension command is calculated using the rolling mill inlet side temperature and the rolling mill outlet side temperature, and the drive device is driven as the operation end. Except for this point, the configuration and functions in FIG. 11 are the same as those in FIG.

  FIG. 12 shows processing performed by the tension command correction unit 1101. First, in step S101, the tension command correction unit 1101 takes in the target value Mbs of the hot rolling mill inlet side temperature from the hot rolling mill inlet side temperature target value storage unit 903. Next, in step S102, the hot rolling mill inlet side temperature target value Mbf is fetched from the hot rolling mill outlet side temperature target value storage means 170. The target value Mbs of the hot rolling mill inlet side temperature and the target value Mbf of the hot rolling mill outlet temperature may be constant, but may be different values depending on the part of the steel sheet.

Further, in step S103, the actual value Mb of the hot rolling mill inlet side temperature is taken from the hot rolling mill inlet side thermometer 902, and the difference ΔFET between them is calculated by the equation (14). ΔFET takes a positive value when the actual temperature value is high.
[Formula 14]
ΔFET = Mbs−Mb (14)
Further, in step S104, the actual value Mf of the hot rolling mill outlet temperature is taken in from the hot rolling mill outlet thermometer 13, and the difference ΔFDT between them is calculated by the equation (15). ΔFDT takes a positive value when the actual temperature value is high.
[Equation 15]
ΔFDT = Mfs−Mf (15)
In step S105, the tension command correction value ΔTf1 is calculated by equation (16) and output. Here, Kt3 and Kt4 are proportional gains.
[Equation 16]
ΔTf1 = Kt3 · ΔFDT + Kt4 · ΔFET (16)
Also, as shown in FIG. 11, the tension command correction value ΔTf1 output from the tension command correction unit 1101 is subtracted from the tension command Tfs output from the tension command storage unit 151, and (Tfs−ΔTf1) becomes a new tension. It becomes a command value.

  The magnitude of the influence of the two temperature deviations (ΔFDT and ΔFET) used in the equation (16) on the compensation value is adjusted by the magnitudes of the proportional gains Kt3 and Kt4. The larger Kt3 is relative to Kt4, the greater the contribution of ΔFDT to the tension command correction value. The larger Kt4 is relative to Kt3, the greater the contribution of ΔFET to the tension command correction value.

  This means that even in the third embodiment of the present invention, the actual value of the hot rolling mill temperature exceeds the target value and becomes higher, resulting in lowering the target tension of the tension control means 152, At this time, a weak tension control is performed.

  Similarly, it means that as the actual value of the hot rolling mill temperature becomes lower than the target value, the target tension of the tension control means 152 is increased, and at this time, the tension control is performed. .

  Further, according to the third embodiment, since the temperature change detected on the upstream side and the temperature change detected on the downstream side are reflected in the control, the control having the characteristics of the first and second embodiments is performed. Can do.

  When multiple stands are installed, the proportional gains Kt3 and Kt4 may be the same between the upstream stands and between the downstream stands, but the tension correction effect is greater between the upstream stands. It is better to make the distance between the upstream stands slightly larger.

  In the present embodiment, a single stand and a looper have been described as an example. However, in a tandem mill having a plurality of stands, the same processing can be realized by preparing the same for each stand and looper.

  According to the third embodiment in which the tension is controlled by the rolling mill entry side temperature Mb and the rolling mill exit side temperature Mf, it is possible to perform control having both the characteristics of the first and second embodiments.

  In FIG. 1, the thermometers 130 and 902 on the exit side and the entry side of the hot rolling mill are thermometers that are already installed for use for other control purposes in the rolling mill control in many cases. This signal is used for tension control. In addition, the hot rolling mill outlet thermometer 130 is installed on the outlet side of the last stand of the plurality of stands, and the hot rolling mill outlet thermometer 902 is installed on the inlet side of the foremost stand of the plurality of stands.

  FIG. 13 shows a fourth embodiment of the present invention. In the first to third embodiments, an example in which the deviation between the tension command value and the actual value is eliminated by the drive speed of the rear stand is shown, but in FIG. 13, the deviation between the tension command value and the actual value is calculated as the looper height. An example to be solved by the change is shown.

  That is, after the output Tfs of the tension command storage unit 151 is corrected by the output ΔTf1 of the tension command correction unit 171, the loop control height correction value Δθ1 is obtained by the tension control unit 1302 using ΔTf which is a deviation from the actual tension value Tf. Is calculated. Looper height control is performed using a value obtained by correcting the looper height command value θs output from the looper height command generation means 1301 by Δθ1 as a looper height command value.

  As described above, as the operation end of the tension control, the drive speeds of the first to third embodiments and the looper height of the present embodiment can be selected, but the present invention can be applied to either case.

  The present invention can be widely applied to looper control of a hot-rolled tandem mill having a looper between finishing stands, such as a conventional mill and a mini mill.

10: Control object 101: Stand 103: Steel plate 108: Looper drive device 109: Drive device 11: Looper 111: Looper cylinder 112: Looper arm 113: Tension meter 114: Height meter 13: Hot rolling mill outlet thermometer 15: Tension control device 151: Tension command storage means 152: Tension control means 153: Speed tuning means 155: Load torque estimation means 156: Looper height command generation means 157: Looper height control means 158: Looper support torque estimation means 170: Heat Hot rolling mill outlet temperature target value 171: Tension command correcting means 901: Tension command correcting means 902: Hot rolling mill inlet side thermometer 903: Hot rolling mill inlet side temperature target value 1101: Tension command correcting means

Claims (11)

A tension control device for a hot rolling mill that includes a plurality of rolling stands and is applied to at least two or more sets of adjacent rolling stands, each of which includes an upstream side rolling stand and a downstream side rolling stand. In the tension control device of a hot rolling mill that has a looper between the stands and controls the tension of the steel plate between the rolling stands to a desired value,
Each set of rolling stands has a tension command storage means for storing a tension command value and a detected temperature from a thermometer for measuring the temperature of the steel sheet, and a tension command obtained from a deviation between the target temperature of the steel sheet and the detected temperature. The tension command correction means for correcting the tension command value according to the correction value of the tension, and the tension control means for adjusting the respective sets of rolling stands according to the deviation between the corrected tension command value and the detected tension value. With
Hot rolling, characterized in that, for a plurality of rolling stands, the correction value of the tension command for the set of upstream rolling stands is set larger than the correction value of the tension command for the set of downstream rolling stands. Machine tension control device. In the tension control device for a hot rolling mill according to claim 1,
A tension control device for a hot rolling mill, wherein weak tension control is performed when the detected temperature of the steel sheet becomes higher than the target temperature, and strong tension control is performed when the detected temperature of the steel sheet falls below the target temperature. In the tension control device for a hot rolling mill according to claim 1 or 2,
The tension command correction means takes in the detected temperature of a hot rolling mill outlet thermometer provided on the outlet side of the hot rolling mill, and according to the deviation between the target temperature on the outlet side of the hot rolling mill and the detected temperature. tension control device for a hot rolling mill, which comprises correcting the tension command value. In the tension control device for a hot rolling mill according to claim 1 or 2,
The tension command correction means takes in the detected temperature of a hot rolling mill inlet side thermometer provided on the inlet side of the hot rolling mill, and according to the deviation of the detected temperature and the target temperature on the hot rolling mill inlet side tension control device for a hot rolling mill, which comprises correcting the tension command value. In the tension control device for a hot rolling mill according to claim 1 or 2,
The tension command correction means includes a first detected temperature detected from a hot rolling mill inlet side thermometer provided on the inlet side of the hot rolling mill and a hot rolling provided on the outlet side of the hot rolling mill. The second detected temperature detected from the machine exit side thermometer is taken in, the deviation between the target temperature on the inlet side of the hot rolling mill and the first detected temperature is calculated as the first temperature deviation, and at the outlet side of the hot rolling mill The tension of the hot rolling mill characterized in that a deviation between the target temperature and the second detected temperature is calculated as a second temperature deviation, and a correction signal is obtained by the sum of the first temperature deviation and the second temperature deviation. Control device. In the tension control device for a hot rolling mill according to any one of claims 1 to 5,
With obtaining the correction value of the tension instruction by multiplying the control gain to the target temperature and the detected temperature deviation of the steel sheet, a plurality of rolling stands, the control gain for the set of rolling stands upstream, downstream of the roll stand set A tension control device for a hot rolling mill, wherein the control gain is set to be large with respect to the control gain. A plurality of rolling stands are provided, and one set of adjacent rolling stands is applied to at least two or more sets, and each set of rolling stands is provided with a looper between an upstream rolling stand and a downstream rolling stand. In the tension control method of a hot rolling mill that controls the tension of the steel sheet passing through to a desired value,
A deviation between the detected temperature of the steel plate and its target temperature is detected, and between the rolling stands, when the detected temperature of the steel plate becomes higher than the target temperature, the tension control is performed, and the detected temperature of the steel plate falls below the target temperature. Sometimes with stronger tension control ,
For a plurality of rolling stands, the value obtained from the deviation of the detected temperature of the steel sheet and its target temperature with respect to the set of upstream rolling stands and the deviation of the detected temperature of the steel sheet and its target temperature with respect to the set of downstream rolling stands A tension control method for a hot rolling mill, characterized in that it is set to be larger than the value obtained from the above . In the tension control method of a hot rolling mill according to claim 7,
The temperature control method for a hot rolling mill is characterized in that the temperature of the steel sheet is a temperature downstream of the hot rolling mill. In the tension control method of a hot rolling mill according to claim 7,
The temperature control method for a hot rolling mill is characterized in that the temperature of the steel sheet is set to a temperature upstream of the hot rolling mill. In the tension control method of a hot rolling mill according to claim 7,
The temperature of the steel sheet is the temperature on the entry side and the temperature on the exit side of the hot rolling mill, and the weak tension control or the strengthen tension control is performed according to the sum of temperature deviations from the respective target temperatures. Tension control method for a hot rolling mill. A plurality of rolling stands are provided, and one set of adjacent rolling stands is applied to at least two or more sets, and each set of rolling stands is provided with a looper between an upstream rolling stand and a downstream rolling stand. In the tension control method of a hot rolling mill that controls the tension of the steel sheet passing through to a desired value,
Detecting the temperature of the steel sheet, with respect to the temperature deviation from the target temperature, when the detected temperature is higher than the target temperature, perform a weaker tension control, and when the detected temperature is lower than the target temperature, perform a stronger tension control,
The correction value obtained by multiplying the deviation between the target temperature and the detected temperature of the steel plate by the control gain is involved in the tension control, and the control gain for the temperature deviation for the upstream set of rolling stands is set to the downstream set. A tension control method for a hot rolling mill, wherein the control gain for the temperature deviation between the rolling stands is set to be large.

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