Method for controlling the steady state time of an intermediate hot coil of a hot rolled steel coil

Abstract

A method for steady-state time control of intermediate hot-rolled steel coils, belonging to the field of control, is disclosed. First, L2 receives the steel coil information and checks if a hot-rolling box indicator is used. If no hot-rolling box indicator is found, an intermediate roller table control system model is adopted until the steel coil is rolled. If a hot-rolling box indicator is found, the hot-rolling box speed and time are calculated; the hot-rolling box control system model is then adopted until the steel coil is rolled. This method, combined with temperature drop control in hot rolling processes using hot-rolling boxes, achieves accurate control of intermediate billet temperature drop, rolling gap, and finishing mill inlet temperature through time-series control of the hot-rolling box. This ensures the stability of the inlet temperature and rolling parameters during hot continuous rolling mill processes, providing a guarantee for the control of finishing mill inlet rolling temperature and rolling parameters during rolling, thereby further improving product performance and quality. It can be widely used in the field of hot-rolling box process control in hot continuous rolling production processes.

Description

Technical Field

[0001] This invention belongs to the field of hot strip steel production process control, and particularly relates to a hot coil box process control method for hot strip rolling. Background Technology

[0002] In recent years, with the continuous development of hot rolling technology, the requirements for the hot rolling performance of strip steel have become increasingly higher. As a result, new requirements have been put forward for the control of rolling temperature. How to control the temperature drop of strip steel is particularly important. In combination with the temperature drop control under the hot rolling box process, how to effectively control the temperature drop of the hot rolling box directly affects the temperature control and the stability of rolling parameters in the subsequent rolling process.

[0003] Figure 1 This is a layout diagram of the intermediate roller table equipment for hot rolling. In the diagram, R2 is the No. 2 roughing mill of hot continuous rolling, and F1 is the No. 1 mill (or No. 1 stand) of the finishing mill. The strip runs from left to right, exiting from R2 and passing through the roller table, hot coil box, flying shear and descaling box in sequence before entering F1.

[0004] Combination Figure 1 As can be seen, after adopting the hot coil box process, the temperature drop of the strip at the entrance of the No. 1 mill of the finishing mill unit changes significantly. Simultaneously, the different speed regimes, descaling water usage regimes, and stand water usage regimes in the finishing mill lead to different changes in the control of the subsequent rolling process. In particular, the finishing mill strategy, which involves selecting different speed regimes and different descaling water and stand water usage regimes based on the use of the hot coil box, directly affects the product quality.

[0005] Meanwhile, the adoption of the hot coil box process requires adaptive coefficients for different rolling force and temperature models for control. Therefore, the finishing rolling strategy needs to select different adaptive coefficients for the rolling force and temperature models depending on whether the hot coil box is used, or create initial values ​​for the adaptive coefficients of rolling force and temperature under the hot coil box mode.

[0006] Chinese invention patent CN 104368599 B, authorized on November 16, 2016, discloses a "method and system for hot continuous rolling of strip steel." The method includes using a hot coil box to uncoil a strip at an initial uncoiling speed VE0 and feeding the strip to a finishing mill for finishing rolling. Before feeding the strip to the first stand of the finishing mill, the uncoiling speed of the hot coil box is adjusted to VE1, where VE1 = VF × h / H + ΔV, where VF is the roll speed of the first stand, H is the initial thickness of the strip, h is the roll gap value of the first stand, and ΔV is 0.03-0.05 m / s. Before feeding the strip to the first stand, its speed is adjusted to be slightly greater than the matching speed VF × h / H obtained according to the flow rate theory per second to meet the bite conditions and avoid slippage. Clearly, this technical solution achieves the matching of the hot coil box unwinding speed with the F1 steel biting speed by adjusting the unwinding speed of the hot coil box, thereby avoiding slippage of the first stand F1 during the steel biting process.

[0007] Chinese invention patent CN 108213084 B, authorized on June 18, 2019, discloses a "method and system for operating control of a hot roll box." The operating control method includes: acquiring detection signals from a first, second, third, fourth, fifth, and sixth hot metal detector; when a detection signal matches a preset first operating condition, issuing a corresponding operating control command based on the detection signal, which instructs the hot roll box to operate according to a preset mode; and when a detection signal matches a preset second operating condition, issuing an alarm to alert personnel for intervention. This technical solution aims to address the problems in existing technologies where subjective differences in manual identification lead to inconsistent process control, product variations, and poor quality.

[0008] Chinese invention patent CN 108543813 B, with authorization announcement date of March 9, 2021, discloses "a process control method for improving the shape of hot-rolled coil boxes," which includes: when the intermediate steel coil billet enters the bending roll, obtaining the roundness of the first half-circle of the intermediate steel coil billet, and adjusting the roll gap and roll surface linear speed of the upper and lower bending rolls; when the intermediate steel coil billet enters the forming roll, adjusting the position of the forming roll up and down according to the roundness of the first half-circle of the intermediate steel coil billet; when the intermediate steel coil billet enters the No. 2 stabilizer, the stabilizer performs dynamic tapping on the intermediate steel coil billet throughout the process to enhance centering control; when the intermediate steel coil billet enters the pinch roll, a trapezoidal negative roll type is used to control the intermediate steel coil billet. This technical solution is used to improve the coil shape and stability of hot coil box operation. It solves the technical problems of non-round inner ring of rolled strip, loose coil, scattered coil, inability to coil, deviation of the steel coil head after uncoiling, and misalignment of the finishing mill. It achieves the technical effects of good coil shape during coiling, stable uncoiling, reduced load on the finishing mill, and improved product surface quality.

[0009] Clearly, the above technical solutions only involve process control of the hot coil box itself, without addressing the issue of achieving relatively steady-state control of the strip running time through variable speed control of the entire hot coil box process, so as to effectively control the rolling gap and temperature drop of the strip at the finishing mill inlet. They also do not consider the issue of ensuring the control of the finishing mill inlet rolling temperature and rolling parameters during the rolling process when using the hot coil box process. Summary of the Invention

[0010] The technical problem to be solved by this invention is to provide a method for controlling the steady-state time of intermediate hot-rolled steel coils. In the case of using a hot-rolling box process, combined with temperature drop control in hot rolling using a hot-rolling box process, this method achieves accurate control of the intermediate billet temperature drop, rolling gap, and finishing mill inlet temperature by controlling the running speed and timing of the hot-rolling box. This ensures the stability of the inlet temperature of the hot continuous rolling mill and the parameters during the rolling process, providing a guarantee for the control of the finishing mill inlet rolling temperature and rolling parameters during the rolling process, thereby further improving product performance and quality.

[0011] The technical solution of this invention is: to provide a method for controlling the steady-state time of intermediate hot-rolled steel coils, including process and equipment control of the hot-rolling process, characterized in that the steady-state time control of intermediate hot-rolled steel coils includes the following steps:

[0012] A. L2 receives information about the steel coil;

[0013] B. Determine if the information for the steel coil includes a mark indicating the use of a hot-rolling box;

[0014] C. If no hot roll box marking is used, proceed to step D); if a hot roll box marking is used, proceed to step E.

[0015] D. Adopt the intermediate roller conveyor control system model until the steel coil is rolled out;

[0016] E. Calculate the speed and time of the hot roll box;

[0017] F. Adopt a hot-rolling box control system model until the steel coil is rolled out.

[0018] The aforementioned method for controlling the steady-state time of intermediate hot-rolled steel coils uses the motion equation of a mass point. Based on the equipment motion characteristics set by L1 and calculated by L2, and by determining whether the hot-rolling box is used, different speed regimes are used during the operation control of the intermediate roller conveyor in L2. Combined with the predicted control of the slab running speed and time when the strip passes through the hot-rolling box, the steady-state time control of the intermediate hot-rolled steel coil is achieved.

[0019] Specifically, the aforementioned method for controlling the steady-state time of intermediate hot-rolled steel coils involves predicting and controlling the speed and time of the strip running on the intermediate roller table, taking into account whether the hot-rolling box is in use. After calculating the running time and temperature at the outlet of the insulation cover, the method combines the temperature drop control of the strip and starts to call the temperature model to control the running speed of the hot-rolling box, thereby achieving steady-state time control of the intermediate hot-rolled steel coils.

[0020] Specifically, the hot-rolled steel coil intermediate hot-rolling steady-state time control method predicts the coiling time and temperature drop in the hot-rolling box, and ensures the finishing mill inlet temperature by adjusting the outlet temperature of R2.

[0021] Specifically, the hot-rolled steel coil intermediate hot-rolling steady-state time control method controls the rolling gap and temperature drop of the strip at the finishing mill entrance to ensure the accuracy of the stand rolling force and strip temperature control during the subsequent finishing mill rolling process.

[0022] Furthermore, the aforementioned hot-rolled steel coil intermediate hot-rolling steady-state time control method achieves relative steady-state control of the strip running time through variable speed control throughout the entire hot-rolling box process, thereby effectively controlling the rolling gap and temperature drop of the strip at the finishing mill inlet and providing a basis for setting finishing mill parameters.

[0023] Specifically, the control modes using the intermediate roller conveyor control system model include:

[0024] 1) When the strip exits the R2 mill, monitor the time from the R2 exit to the hot coil box inlet;

[0025] 2) When the strip arrives at the hot coil box inlet, monitor the time it takes for the head of the hot coil box to decelerate to the threading speed;

[0026] 3) When the strip reaches the bending roll, monitor the time it takes for the head to be threaded and coiled.

[0027] 4) Core formation, monitoring the time when acceleration begins after the inner ring is established;

[0028] 5) Inward rolling has been established and acceleration has begun; monitor the hot rolling box winding operation time.

[0029] 6) The pinch rolls are raised and the support rolls are lowered. Monitor the time when the tail of the strip begins to decelerate as it enters the inlet roller table of the hot coil box.

[0030] 7) Tail tracking begins; monitor tail positioning time.

[0031] 8) Automatic tail end positioning and monitoring, monitoring the time from when the curling is complete to when it stops;

[0032] 9) The steel coil is now rolled up.

[0033] Specifically, the control modes using the hot roll box control system model include:

[0034] 1) Once the hot coil box starts uncoiling, monitor the time it takes for the strip head to accelerate to the shearing speed;

[0035] 2) The strip head enters the flying shear zone, and the time it takes for the strip to travel within the flying shear zone is monitored;

[0036] 3) Shearing the strip head, monitoring the time it takes for the strip to decelerate to the F1 synchronous speed;

[0037] 4) Monitor the time it takes for the strip head to leave the flying shear area and reach the F1 entrance;

[0038] 5) The strip head enters F1.

[0039] Furthermore, in the aforementioned method for controlling the steady-state time of intermediate hot-rolled steel coils, the time control from the tail of the strip to the end of the hot-rolling box is divided into:

[0040] 1) The running time from the R2 temperature measuring instrument at the tail end of the strip to the hot rolling box threading speed at the head end;

[0041] 2) The time when the strip head winding ends.

[0042] Furthermore, after the strip is uncoiled, its speed control logic is as follows:

[0043] 1) Accelerate from 0 to shear speed Vcut;

[0044] 2) Maintain the cutting speed while cutting the head;

[0045] 3) Decelerate to F1 belt-threading speed Vf1

[0046] 4) Keep Vf1 in F1 rack.

[0047] Compared with the prior art, the advantages of the present invention are:

[0048] 1. This technical solution achieves relatively steady-state control of the strip running time through variable speed control of the entire hot rolling box process. It can effectively control the rolling gap and temperature drop of the strip at the finishing mill inlet, and at the same time, provide a basis for setting finishing mill parameters, so as to control the rolling gap and temperature drop of the strip at the finishing mill inlet, and ensure the accuracy of the stand rolling force and strip temperature control in the subsequent finishing mill rolling process;

[0049] 2. The speed control in this technical solution adopts the motion equation of a mass point, that is, it is based on the equipment motion characteristics set by L1 (basic automation computer) and the equipment motion characteristics calculated by L2 (process control computer). By distinguishing whether the hot coil box is used, different speed control systems are adopted during the L2 intermediate roller table operation control process. At the same time, combined with the slab running speed and time prediction control when the strip passes through the hot coil box, the steady-state time control of the intermediate hot coil is realized.

[0050] 3. By adopting this technical solution for speed control in the hot rolling process, a corresponding finishing rolling strategy can be specified, thereby improving the stability of parameters during the finishing rolling process;

[0051] 4. This technical solution ensures the finishing mill inlet temperature by predicting the coiling time and temperature drop in the hot coil box and adjusting the outlet temperature of R2;

[0052] 5. Predicting the time of the hot coil box can provide a basis for setting the steel extraction rhythm. Attached Figure Description

[0053] Figure 1 This is a layout diagram of the hot rolling intermediate roller conveyor equipment;

[0054] Figures 1-1 to 1-8 This is a schematic diagram of the operation process and related control modes of the strip head;

[0055] Figure 2 This is a schematic diagram of the steady-state time control of the intermediate hot-rolled steel coil operating speed.

[0056] Figure 3 This is a schematic diagram illustrating the control of the uncoiling speed during the steady-state time of the intermediate hot-rolled steel coil.

[0057] Figure 4 This is a block diagram of the main process for controlling the steady-state time of intermediate hot-rolled steel coils in this invention.

[0058] Figure 5 This is a block diagram of the hot-rolled steel coil intermediate hot-rolling steady-state time control coiling process of the present invention;

[0059] Figure 6This is a flowchart of the uncoiling process for controlling the steady-state time of intermediate hot-rolled steel coils according to the present invention. Detailed Implementation

[0060] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0061] In this technical solution and during actual on-site control, the operation process and related control modes of the strip head can be described as follows:

[0062] 1.) The rolling speed and threading speed between the roughing mill and the hot coil box are synchronized, such as... Figure 1-1 As shown;

[0063] 2.) The strip head (also known as the strip head, or simply the head) begins tracking and then reaches the bending roll, as shown below. Figure 1-2 As shown;

[0064] 3.) Core formation, such as Figure 1-3 As shown;

[0065] 4.) The in-roll has been established (number of turns or length), and the roughing mill, hot coil box, and inter-roller area accelerate to the coiling speed, such as... Figure 1-4 As shown;

[0066] 5.) As the roll diameter increases, the upper pinch roller slowly rises, and the 1CR support roller slowly descends, as... Figure 1-5 As shown;

[0067] 6.) Tracking begins at the tail end of the strip (also known as the strip tail, or simply the tail or strip tail), then decelerates to a creeping speed, such as... Figure 1-6 As shown;

[0068] 7.) Automatic tail end positioning control begins, such as... Figure 1-7 As shown;

[0069] 8.) After winding is complete, the 1CR support roller drive stops, the strip is in the unwinding position, and the 1CR descends to 0 degrees (horizontal direction). Figure 1-8 As shown.

[0070] Based on the above operating process and related control modes, this technical solution controls the motion trajectory of the strip head as follows: Figure 2 As shown.

[0071] Based on the above description, the running time of the strip in the hot coil box can be calculated as follows:

[0072] 1. The time T1 taken for the strip steel to travel from the R2 outlet temperature measuring instrument to the hot coil box:

[0073] T1 = S1 / V1 (unit: s)

[0074] Wherein, S1 is the distance (physical location, unit: m) from the strip head (also known as the intermediate billet head, or simply the head) from the roughing mill exit temperature measuring instrument (point 1) to deceleration point 2; V1 is the speed (unit: m / s) of the head from the roughing mill exit (point 1) to deceleration point 2.

[0075] 2. The time T2 for the hot roll box head to decelerate to the threading speed:

[0076] T2 = 2*S2 / (Vthr + V1) (unit: s)

[0077] Where Vthr is the threading speed of the hot roll box (unit: m / s); S2 is the distance (physical position, unit: m) from deceleration point 2 to the threading start point at the head of the hot roll box; a1=(Vthr^2-V1^2) / 2*S2; a1 is the deceleration of the threading speed of the synchronous hot roll box (unit: m / s2).

[0078] Explanation: The deceleration is determined by the difference between the initial and final speeds and the deceleration distance, in order to control the temperature drop and reduce deceleration time and current fluctuations.

[0079] 3. Time T3 for putting on the head strap:

[0080] T3 = S3 / Vthr (unit: s)

[0081] Where S3 is the length of the head threading speed (process requirement length, unit: m).

[0082] 4. Time T4: The time from the start of inner circle establishment to the curling speed.

[0083] T4 = (Vrun - Vthr) / a2 (unit: s);

[0084] Where Vrun is the operating speed of the hot roll box (unit: m / s2); a2 is the acceleration from the start of inner ring establishment to the rolling speed.

[0085] Instructions: After threading the strap onto the head, accelerate as quickly as possible to achieve the highest curling speed, in order to reduce the curling time.

[0086] 5. The high-speed winding operation time T5 of the hot roll box:

[0087] T5 = S5 / Vrun (unit: s);

[0088] Wherein, S5 is the length wound at the hot coil box running speed; S5 = L - S4 - S6 - S7 (unit: m); L is the length of the intermediate billet; S4 is the distance from the start of acceleration to the coiling speed at the inner ring establishment; S4 = ((Vrun + Vthr) / 2) * T4; S6 is the distance from the start of deceleration at the tail of the hot coil box to the tail coiling point when it enters the inlet roller table (physical position unit: m); S7 is the length running at the tail coiling speed (process requirement length, unit: m);

[0089] Explanation: The intermediate billet (strip) is processed by removing the acceleration distance at the head and the deceleration and coiling distance at the tail. It runs at the highest speed in the middle to reduce the coiling time of the intermediate billet.

[0090] 6. The time T6 during which the hot roll box begins to decelerate to the tail winding speed after entering the inlet roller conveyor at the tail end:

[0091] T6 = 2*S6 / (Vtail + Vrun) (unit: s);

[0092] Where Vtail is the tail curling speed (unit: m / s); a3=(Vtail^2-Vrun^2) / 2*S6; a3 is the deceleration from the highest speed to the tail curling.

[0093] Explanation: The deceleration is determined by the difference between the initial and final velocities and the deceleration distance, in order to reduce deceleration time and current fluctuations.

[0094] 7. Hot roll box tail positioning time T7:

[0095] T7 = S7 / Vtail (unit: s)

[0096] S7 represents the length at which the tail curls (the required length is in meters).

[0097] 8. Time T8 from the completion of hot rolling in the hot rolling box to the stop:

[0098] T8 = (Vtail) / a4 (unit: s)

[0099] Where: a4 is the deceleration from the tail curling speed to a stop.

[0100] Therefore, the time taken from the head point entering the hot roll box until it is unwound can be obtained as follows:

[0101] TT=T1+T2+T3+T4+T5+T6+T7+T8+T0

[0102] The definitions and descriptions of T1 to T8 are as described above, and T0 is the waiting time for opening the book.

[0103] Therefore, in the technical solution of this invention, the time control from the tail end to the end of the hot winding box is divided into:

[0104] 1) The running time from the R2 temperature measuring instrument at the tail end to the hot roll box threading speed at the head end;

[0105] 2) The time when the head winding ends.

[0106] After the book is unrolled, the tail becomes the head, and its speed control logic is as follows:

[0107] 1) Accelerate from 0 to shear speed Vcut;

[0108] 2) Maintain the cutting speed while cutting the head;

[0109] 3) Decelerate to F1 belt-threading speed Vf1

[0110] 4) Keep Vf1 in F1 rack.

[0111] At this point, the time it takes for the new strip head to reach F1 can be calculated as follows:

[0112] 9. Time T9 for hot roll box unwinding acceleration to shearing speed:

[0113] T9 = Vcut / a5 (unit: s)

[0114] Where: Vcut is the shearing velocity; a5 is the acceleration of the synchronous shearing velocity.

[0115] Note: The shearing speed and equipment position are both fixed, that is, Vcut and S9 are constant accelerations, and a5 is also a constant.

[0116] 10. Time T10 from the strip head to the completion of shearing:

[0117] T10 = S10 / Vcut (unit: s)

[0118] Where: S10 is the length of the shearing speed operation (process requirement length, unit: m).

[0119] 11. The time T11 for the strip to decrease from the shearing speed to the F1 speed:

[0120] T11 = 2 * S11 / (Vf1 + Vcut) (unit: s)

[0121] a6=(Vf1^2-Vcut^2) / 2*S11

[0122] Where: a6 is the acceleration of the synchronous F1 speed; Vf1 is the F1 mill speed.

[0123] Explanation: The deceleration is determined by the difference between the initial and final speeds and the deceleration distance, in order to control the temperature drop of the intermediate billet and reduce deceleration time and current fluctuations.

[0124] 12. Time T12 for the strip head to enter F1:

[0125] T12 = S12 / Vf1 (unit: s)

[0126] Where: S12 is the running length at F1 speed, the same as the length of the intermediate billet.

[0127] Therefore, the time taken from the end of the rollout at the head point until F1 is:

[0128] TF = T9 + T10 + T11 + T12

[0129] Based on the above description and control approach, the main flow of steady-state time control for intermediate hot-rolled steel coils in this technical solution can be obtained as follows: Figure 4 As shown in the image.

[0130] exist Figure 4 In this technical solution, the main process for controlling the steady-state time of intermediate hot-rolled steel coils includes:

[0131] A. L2 receives information about the steel coil;

[0132] B. Determine if the information for the steel coil includes a mark indicating the use of a hot-rolling box;

[0133] C. If no hot roll box marking is used, proceed to step D); if a hot roll box marking is used, proceed to step E.

[0134] D. Adopt the intermediate roller conveyor control system model until the steel coil is rolled out;

[0135] E. Calculate the speed and time of the hot roll box;

[0136] F. Adopt a hot-rolling box control system model until the steel coil is rolled out.

[0137] The technical solution of this invention, through variable speed control of the entire hot rolling box process, achieves relatively steady-state control of the strip running time, enabling effective control of the rolling gap and temperature drop of the strip at the finishing mill inlet. Simultaneously, it provides a basis for setting finishing mill parameters, thereby controlling the rolling gap and temperature drop of the strip at the finishing mill inlet to ensure the accuracy of the stand rolling force and strip temperature control during subsequent finishing mill rolling processes.

[0138] Meanwhile, the technical solution of the present invention adopts the motion equation of a mass point for speed control, that is, it is based on the equipment motion characteristics set by L1 (basic automation) and the equipment motion characteristics calculated by L2 (process control machine). By judging whether the hot coil box is used, different speed control systems are adopted during the operation control of the intermediate roller conveyor of L2 (process control machine). At the same time, combined with the slab running speed and time prediction control when the strip passes through the hot coil box, the steady-state time control of the intermediate hot coil of the steel coil is realized.

[0139] Furthermore, in the technical solution of the present invention, when predicting and controlling the running speed and time of the strip on the intermediate roller table, the speed and time of the strip on the intermediate roller table are predicted and controlled in conjunction with whether the hot coil box is used. After calculating the running time and temperature at the outlet of the heat insulation cover, the running speed of the hot coil box is controlled by calling the temperature model in conjunction with the temperature drop control of the strip, thereby realizing the steady-state time control of the intermediate hot coil of the steel coil.

[0140] Furthermore, the hot-rolled steel coil intermediate hot-rolling steady-state time control coiling process of this technical solution is as follows: Figure 5 As shown in the image.

[0141] exist Figure 5 In this technical solution, the intermediate hot-rolled steel coil steady-state time control coiling process (also known as the intermediate roller table control system model) includes:

[0142] 1. When the strip exits the R2 mill, control (or monitor, the same below) T1 (time from R2 exit to hot coil box inlet);

[0143] 2. When the strip arrives at the hot coil box inlet, control T2 (the time it takes for the head of the hot coil box to decelerate to the threading speed);

[0144] 3. When the strip reaches the bending roll, control T3 (head threading and coiling time);

[0145] 4. Core formation, controlling T4 (the time when acceleration begins after the inner ring is formed);

[0146] 5. Inward rolling has been established and acceleration has begun; control T5 (hot roll box winding operation time);

[0147] 6. Raise the pinch rolls and lower the support rolls to control T6 (the time when the tail of the strip begins to decelerate as it enters the inlet roller table of the hot coil box);

[0148] 7. Start tail tracking and control T7 (tail positioning time);

[0149] 8. Automatic tail-end positioning control, controlling T8 (the time from when the curling is completed to when it stops);

[0150] 9. The steel coil is now rolled up.

[0151] Furthermore, the unwinding control process in the technical solution of this invention is as follows: Figure 6 As shown in the image.

[0152] exist Figure 6 In this technical solution, the hot-rolled steel coil intermediate hot-rolling steady-state time control uncoiling process includes:

[0153] 1) When the hot coil box starts uncoiling, control T9 (the time it takes for the strip head to accelerate to the shearing speed);

[0154] 2) The strip head enters the flying shear zone, and T10 (the time the strip runs within the flying shear zone) is controlled.

[0155] 3) Shearing of the strip head, controlling T11 (the time for the strip to decelerate to the synchronous speed of F1);

[0156] 4) When the strip head leaves the flying shear area, control the T12 (the time from when the strip head leaves the flying shear area to the F1 entrance);

[0157] 5) The strip head enters F1.

[0158] Example:

[0159] A hot rolling mill produces slabs 10.8m long, 1.4m wide, and 0.23m thick. The R2 exit length is 58.15m, width is 1.3m, and thickness is 0.042m. The uncoiling wait time is 10s, the F1 rolling speed is 0.65m / s, and the hot coil box parameters are as follows:

[0160] 40 2.5 3.5 0.7 45 2.25 3.2 0.7 50 2 3 0.6 55 1.8 2.8 0.6 60 1.6 2.5 0.5

[0161] S1 = 21.75m (distance from temperature measuring point 1 at R2 exit to deceleration point 2)

[0162] S2 = 4m (distance from deceleration point 2 to the starting point of the belt threading at the head of the hot roll box)

[0163] S3 = 2m (the length of the path traveled by the head strap threading speed)

[0164] S6 = 5m (distance from the monitoring point at the tail of the hot roll box to the tail curling point)

[0165] S7 = 2m (distance of tail curl)

[0166] S10 = 1m (length of shear velocity travel)

[0167] S11 = 1m (distance from the end of shearing to the F1 inlet)

[0168] a2 = 1.2 m / s2 (The acceleration from the start of the inner ring's formation to the curling speed, taken as the highest allowable acceleration by electrical means)

[0169] a4 = 1.2 m / s² (Deceleration from tail curling speed to stop, taken as the maximum allowable deceleration by electrical parameters)

[0170] a5 = 1.2 m / s² (acceleration of synchronous shear velocity)

[0171] V1 = 3.4 m / s (velocity of the head from roughing mill exit point 1 to deceleration point 2)

[0172] Vthr = 2.5 m / s (threading speed in the hot roll box)

[0173] Vrun = 3.5 m / s: (Speed ​​of the hot roll box)

[0174] Vtail = 0.7 m / s: (tail curling speed)

[0175] Vcut = 1.2 m / s (shearing velocity)

[0176] Vf1 = 0.65 m / s (F1 mill speed)

[0177] Based on the above equipment and operating parameters, the following calculations and control strategies are proposed:

[0178] 1. The time taken for the strip steel to travel from the R2 outlet temperature measuring instrument to the hot coil box:

[0179] T1 = S1 / V1

[0180] T1 = 21.75 / 3.4 = 6.4

[0181] 2. Time taken for the hot roll box head to decelerate to the threading speed:

[0182] T2=2*S2 / (Vthr+V1)=2*4 / (2.5+3.4)=1.36

[0183] a1=(Vthr^2-V1^2) / 2*S2=(2.5^2-3.4^2) / (2*4)=-0.885

[0184] 3. Duration of head strap application:

[0185] T3 = S3 / Vthr

[0186] T3 = 2 / 2.5 = 0.8

[0187] 4. Time from the start of inner circle establishment to the curling speed:

[0188] T4=(Vrun-Vthr) / a2

[0189] T4 = (3.5 - 2.5) / 1.2 = 0.83

[0190] 5. High-speed winding operation time of the hot roll box

[0191] S4=((Vrun+Vthr) / 2)*T4

[0192] S4 = (3.5 + 2.5) / 2 * 0.83 = 2.5

[0193] S5=L-S4-S6-S7=58.15-2.5-5-2=48.65

[0194] T5 = S5 / Vrun

[0195] T5 = 48.65 / 3.5 = 13.9

[0196] 6. The time it takes for the hot roll box to decelerate to its tail winding speed after entering the inlet roller conveyor at the tail end:

[0197] T6 = 2 * S6 / (Vtail + Vrun) = 2 * 5 / (0.7 + 3.5) = 2.38 (unit: s)

[0198] a3=(Vtail^2-Vrun^2) / 2*S6=(0.7^2-3.5^2) / (2*5)=-1.176

[0199] 7. Positioning time at the tail of the hot roll box:

[0200] T7 = S7 / Vtail

[0201] T7 = 2 / 0.7 = 2.86

[0202] 8. Time from completion of hot rolling in the hot rolling box to stopping:

[0203] T8 = Vtail / a4

[0204] T8 = 0.7 / 1.2 = 0.5833

[0205] TT=T1+T2+T3+T4+T5+T6+T7+T8+T0

[0206] = 6.4 + 1.36 + 0.8 + 0.83 + 13.9 + 2.38 + 2.86 + 0.58 + 10

[0207] =39.11s

[0208] Similarly, the time for the new strip head to reach F1 can be calculated as follows:

[0209] 9. Time from unwinding in the hot coil box to the shearing speed:

[0210] T9 = Vcut / a5

[0211] T9 = 1.2 / 1.2 = 1

[0212] 10. Time from the strip head to the completion of shearing:

[0213] T10 = S10 / Vcut

[0214] T10 = 1 / 1.2 = 0.833

[0215] 11. Time for the strip to decrease from shear speed to speed F1:

[0216] T11=2*S11 / (Vf1+Vcut)=2*1 / (0.65+1.2)=1.08

[0217] a6=(Vf1^2-Vcut^2) / 2*S11=(0.65^2-1.2^) / (2*1)=-0.51

[0218] 12. Time it takes for the strip head to enter F1:

[0219] T12=S12 / Vf1

[0220] T12 = 58.15 / 0.65 = 89.46

[0221] Therefore, the time taken from the start of the rollout to F1 can be obtained:

[0222] TF = T9 + T10 + T11 + T12

[0223] = 1 + 0.833 + 1.08 + 89.46

[0224] =92.373

[0225] Therefore, the time from hot rolling to uncoiling of the slab is 39.11s, and the time from uncoiling to the completion of F1 rolling is 92.373s.

[0226] The technical solution of this invention achieves relatively steady-state control of the strip running time, thereby effectively controlling the rolling gap and temperature drop of the strip at the finishing mill inlet. This provides a basis for setting finishing mill parameters and ensures the accuracy of the stand rolling force and strip temperature control during subsequent finishing mill rolling processes. Its speed control employs the particle motion equation, using a flag indicating whether the hot coil box is used to determine different speed regimes during the L2 intermediate roller table operation. Simultaneously, combined with the predicted control of the slab running speed and time when the strip passes through the hot coil box, steady-state time control of the intermediate hot coiling is achieved. After adopting this technical solution for speed control in the hot coiling process, corresponding finishing mill rolling strategies can be specified, improving the stability of parameters during the finishing mill rolling process. By predicting the coiling time and temperature drop at the hot coil box and adjusting the exit temperature of R2, the finishing mill inlet temperature is ensured.

[0227] This invention can be widely used in the field of hot coil box process control in hot continuous rolling production.

Claims

1. A method for controlling the steady-state time of intermediate hot-rolled steel coils, comprising process and equipment control of the hot-rolling process, characterized in that: The aforementioned hot-rolled steel coil intermediate hot-rolling steady-state time control includes the following steps: A. L2 receives information about the steel coil; B. Determine if the information for the steel coil includes a mark indicating the use of a hot-rolling box; C. If no hot roll box marking is used, proceed to step D); if a hot roll box marking is used, proceed to step E. D. Adopt the intermediate roller conveyor control system model until the steel coil is rolled out; E. Calculate the speed and time of the hot roll box; F. Adopt a hot-rolling box control system model until the steel coil is rolled out; Specifically, the intermediate hot-rolled steel coil steady-state time control coiling process includes: 1) When the strip exits the R2 mill, monitor the time from the R2 exit to the hot coil box inlet; 2) When the strip arrives at the hot coil box inlet, monitor the time it takes for the head of the hot coil box to decelerate to the threading speed; 3) When the strip reaches the bending roll, monitor the time it takes for the head to thread and coil the strip; 4) Core formation, monitoring the time when acceleration begins after the inner ring is established; 5) Inward rolling has been established and acceleration has begun; monitor the hot roll box winding operation time. 6) The pinch rolls are raised and the support rolls are lowered. Monitor the time when the tail of the strip begins to decelerate as it enters the inlet roller table of the hot coil box. 7) Tail tracking begins; monitor tail positioning time. 8) Automatic tail end positioning and monitoring, monitoring the time from when the curling is complete to when it stops; 9) The steel coil is now rolled up; Its hot-rolled steel coil intermediate hot-rolled steady-state time control uncoiling process includes: 1) Once the hot coil box starts uncoiling, monitor the time it takes for the strip head to accelerate to the shearing speed; 2) The strip head enters the flying shear zone, and the time it takes for the strip to travel within the flying shear zone is monitored; 3) Shearing the strip head, monitoring the time it takes for the strip to decelerate to the F1 synchronous speed; 4) Monitor the time it takes for the strip head to leave the flying shear area and reach the F1 entrance; 5) The strip head enters F1; The aforementioned method for controlling the steady-state time of intermediate hot-rolled steel coils uses a particle motion equation for speed control. Based on the equipment motion characteristics set by L1 and calculated by L2, and by determining whether the hot-roll box is used, different speed control regimes are adopted during the L2 intermediate roller conveyor operation control process. Combined with the slab running speed and time prediction control when the strip passes through the hot-roll box, the steady-state time control of intermediate hot-rolled steel coils is achieved. The aforementioned hot-rolled steel coil intermediate hot-rolling steady-state time control method achieves relative steady-state control of the strip running time by controlling the variable speed of the hot-rolling box throughout the entire process. This enables effective control of the rolling gap and temperature drop of the strip at the finishing mill inlet, and provides a basis for setting finishing mill parameters. This ensures the accuracy of the stand rolling force and strip temperature control during the subsequent finishing mill rolling process.

2. The method for controlling the steady-state time of intermediate hot-rolled steel coils according to claim 1, characterized in that: The aforementioned method for controlling the steady-state time of intermediate hot-rolled steel coils involves predicting and controlling the speed and time of the strip running on the intermediate roller table, taking into account whether the hot-rolling box is in use. After calculating the running time and temperature at the outlet of the insulation cover, the method combines the strip's temperature drop control with the start of calling the temperature model to control the running speed of the hot-rolling box, thereby achieving steady-state time control of the intermediate hot-rolled steel coils.

3. The method for controlling the steady-state time of intermediate hot-rolled steel coils according to claim 1, characterized in that: The aforementioned method for controlling the steady-state time of intermediate hot-rolled steel coils predicts the coiling time and temperature drop in the hot-rolling box and ensures the entry temperature of the finishing mill by adjusting the exit temperature of R2.

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