Method for simultaneously controlling rough rolling exit temperature and finish rolling entry temperature of IF steel ferrite strip

Abstract

The present application relates to a kind of IF steel ferrite strip steel rough rolling outlet temperature and finish rolling entrance temperature simultaneous control method, belong to the control method technical field specially applicable to metal rolling mill.This method sets the oscillation interval between R1 rolling mill and R2 rolling mill in existing rolling production line, uses the temperature calculation model of existing rolling production line to read the entrance temperature of strip steel in oscillation area in the 6th pass of R2, iteratively calculates the oscillation time and the outlet temperature T1 of strip steel in R2, in addition to making T1 close to the specified rough rolling target outlet temperature T0, further makes T1 close to the actual oscillation time determined after T0 is corrected T and executes oscillation;In addition, according to the deviation of measured rough rolling outlet temperature and finish rolling entrance temperature, the delay unwinding time of hot coil box is controlled, so that rough rolling outlet temperature and finish rolling entrance temperature are simultaneously controlled to reach the target temperature specified in production.

Description

Technical Field

[0001] This invention relates to a method for ensuring that the roughing mill exit temperature and finishing mill inlet temperature simultaneously meet production requirements during the rolling of IF steel basalt strip, and belongs to the technical field of control methods specifically applicable to metal rolling mills. Background Technology

[0002] IF steel ferrite rolling process as follows Figure 1 As shown: The strip steel passes through the furnace front roller table, descaling box, and R1 mill for rolling, and then undergoes reversible rolling on the R2 reversible mill. After reversible rolling, it enters the hot coil box for coiling. After coiling in the hot coil box, it is uncoiled only after the hot coil box scraper is in place. After uncoiling, it enters the finishing mill for rolling. Thermometers are generally placed at the entrance and exit of the R2 mill and the entrance of the finishing mill. In the area from the heating furnace to the exit of the R1 mill (entrance of the R2 mill), due to environmental factors and iron oxide scale on the surface of the strip steel, accurate measurement is not possible, therefore thermometers are not installed. The rolling temperature requirements for IF steel strip are as follows: the furnace exit temperature is about 1120°C, the finishing mill inlet temperature is ≤840°C, and after roughing, the strip temperature drops by 280°C before the finishing mill inlet to achieve the required inlet temperature of ≤840°C. Therefore, the target exit temperature of the roughing mill must be controlled at ≤860°C (the temperature drop between the pyrometer at the R2 exit of the roughing mill and the pyrometer at the finishing mill inlet is usually about 20°C).

[0003] For rolling lines without water cooling equipment, to achieve significant temperature reduction, a swing zone is typically added between the R1 and R2 mills. The roughing mill rolling pattern is set to 1+7, with the last pass skipped (i.e., R1 rolls 1 pass, R2 rolls 6 passes, and the 7th R2 pass is skipped). After the strip is rolled 7 passes, air cooling and thermal radiation are used to achieve swing cooling in the swing zone. During swinging, the operator observes the thermometer at the R2 inlet or outlet and manually stops the swing once the required temperature is reached. However, this control method cannot reliably guarantee that the actual roughing mill outlet temperature and finishing mill inlet temperature reach the target production temperature.

[0004] A Chinese patent with publication number CN111250545A discloses a control system and method for reducing the over-thickness rate of oscillating steel coils. This system and method address the problem of excessive thickness at the finishing mill exit when the strip oscillates. The solution is to recalculate and adjust the finishing mill inlet temperature based on the oscillation time. However, this adjustment of the finishing mill inlet temperature is not intended to make the actual finishing mill inlet temperature close to the target finishing mill inlet temperature. It only aims to prevent the finishing mill exit from being over-thick based on the oscillation time, and cannot guarantee that the roughing mill exit temperature and the finishing mill inlet temperature meet the standards.

[0005] Chinese patent CN103990653A discloses a method for ensuring the accuracy of the finishing mill inlet temperature. This method calculates the roughing mill outlet temperature T2 based on the furnace exit temperature T0, and then calculates the roughing mill outlet temperature T1 based on FTO and speed. According to the method's specification, with an iteration cycle of 300ms and an upper limit of 180 iterations, the maximum oscillation time is 54 seconds and the maximum temperature drop is 82°C. However, the general requirement for the overall temperature drop in roughing milling is around 130°C, which fails to meet the requirements for the roughing mill outlet temperature and finishing mill inlet temperature in IF steel production. Summary of the Invention

[0006] The technical problem to be solved by this invention is: how to simultaneously achieve the target exit temperature of roughing and the target inlet temperature of finishing in the strip rolling of IF ferrite.

[0007] The technical solution proposed by this invention to solve the above-mentioned technical problems is: a method for simultaneously controlling the exit temperature of roughing mill and the inlet temperature of finishing mill for IF steel rib strip, involving two roughing mill stations R1 and R2 in the rolling production line, a hot coil box, and an existing temperature calculation model of the rolling production line, and performing the following steps:

[0008] S1. Set the roughing mode of one pass for R1 and seven passes for R2, and let the seventh pass of R2 pass empty. Set the swing zone between the R1 mill and the R2 mill, and enter the swing zone after the R2 mill completes the sixth pass to start calculating the swing time and swinging.

[0009] S2. Read the temperature calculation model and calculate the inlet temperature T of the strip in the swing zone in the sixth pass of R2. 入口 ;

[0010] S3. Calculate the exit temperature T1 of the strip at R2 using the following formula (1) iteratively.

[0011] T1 = T_inlet - T_temperature drop (1),

[0012] In equation (1), T1 is the outlet temperature of the strip at R2 calculated iteratively, and T_temperature drop is the temperature drop of the strip from the inlet of the pre-swinging zone of R2 to the outlet of R2, calculated according to equation (2).

[0013] Temperature drop T = W * t1 (2),

[0014] In equation (2), W is the temperature drop per unit time of the strip from the inlet to the outlet of R2 in the swing zone before R2 calculated by the temperature calculation model, and t1 is the swing time calculated in the current iteration after iterative calculation. The iterative calculation of t1 is expressed as in equation (3).

[0015] t1=t10+(T10-T0)*G, (3),

[0016] In equation (3), T10 is the exit temperature of the strip at R2 calculated in the previous iteration, T0 is the target exit temperature of the roughing mill at R2 specified in production, G is a coefficient in seconds / ℃, and t10 is the oscillation time calculated in the previous iteration.

[0017] The temperature drop and T1 are calculated iteratively starting from the initial value according to the calculated oscillation time;

[0018] S4. Compare T1 calculated in each iteration with T0.

[0019] If |T1-T0|≥1, then repeat step S3;

[0020] If |T1-T0| < 1, then stop the calculation, output the currently calculated swing time t1 as the time when the strip enters the swing and execute the swing;

[0021] S5. Calculate the temperature deviation dR at the exit of the roughing mill of the previous rolled strip according to the following formula (4).

[0022] dR=T R2 -T0 (4),

[0023] In equation (4), T R2 T0 is the measured roughing mill exit temperature of the previous rolled strip, and T0 is the target roughing mill exit temperature required for production.

[0024] S6. Calculate the delayed unwinding time of the hot roll box according to the following formula (5): DelayT

[0025] DelayT=DelayT0+dR*G1 (5)

[0026] In equation (5), DelayT0 is the initial value of the hot roll box delay unwinding time, and G1 is a constant;

[0027] S7. Control the hot roll box to delay unwinding according to the calculated hot roll box delay unwinding time DelayT.

[0028] The beneficial effects of this invention are as follows: First, by linking the temperature drop Ttemperature drop calculated at the R2 exit of the strip with the set oscillation time t1, that is, by associating the calculated exit temperature T1 of the strip at R2 with the oscillation time t1, the oscillation time is iteratively calculated from an initial value to T1 and compared with the target exit temperature T0 specified for roughing mill R2. When the difference between the calculated T1 and T0 is large, the calculation of t1 and T1 continues iteratively. When the calculated T1 and T0 are close, the calculation stops and the currently calculated oscillation time is output as the time for the strip to enter the oscillation and the oscillation is executed. Therefore, in the IF steel slab rolling process, the strip can be oscillated between R1 and R2 according to the oscillation time close to the target exit temperature T0 specified for roughing mill, thereby controlling the roughing mill exit (R2 exit) temperature to reach the target exit temperature T0 specified for roughing mill as much as possible. Second, if the measured roughing mill exit temperature deviates from the target, the delayed uncoiling time of the hot coil box is calculated based on the roughing mill exit temperature deviation dR. Then, the delayed uncoiling time of the hot coil box is controlled to ensure the finishing mill inlet temperature reaches the production-specified finishing mill exit target temperature. Third, the roughing mill corrected target exit temperature T is obtained by correcting the deviation between the previously measured strip temperature and the specified roughing mill target exit temperature. That is, the pre-specified production target temperature is corrected based on the measured temperature. By iteratively calculating the roughing mill exit temperature T1 using the oscillation time, it becomes closer to the actual roughing mill target exit temperature T, thus allowing for more precise control of the roughing mill exit (R2 exit) temperature to reach the production-specified roughing mill exit target temperature T0. Fourth, if not only the measured roughing mill exit strip temperature deviates from the target, but the measured finishing mill inlet temperature also deviates, the delayed uncoiling time of the hot coil box is further calculated based on the finishing mill inlet temperature deviation dF. This allows for more precise control of the delayed uncoiling time of the hot coil box, further controlling the finishing mill inlet temperature to reach the production-specified finishing mill exit target temperature.

[0029] Furthermore, in step S3, the iterative calculation of t1 is expressed as follows (6):

[0030] t1=t10+(T10-T)*G, (6)

[0031] In equation (6), T is the roughing mill correction target exit temperature, which is corrected based on the measured roughing mill exit temperature and is calculated according to the following equation (7).

[0032] T = T0 - Tv (7),

[0033] In equation (7), Tv is the correction value for the roughing target exit temperature of the current rolled strip, which is calculated and expressed in equation (8).

[0034] Tv=Tv0+dR*Ga (8),

[0035] In equation (8), Tv0 is the correction value of the target exit temperature of the previous rolled strip, Ga is a constant, dR is the deviation of the exit temperature of the previous rolled strip, and dR = the measured exit temperature of the previous rolled strip - the target exit temperature of the previous rolled strip T0.

[0036] The temperature drop and T1 are calculated iteratively starting from the initial value according to the oscillation time;

[0037] In step S4, T1 calculated in each iteration is compared with T.

[0038] If |T1-T| ≥ 1, then repeat step S3;

[0039] If |T1-T| < 1, then stop the calculation, output the currently calculated swing time t1 as the time when the strip enters the swing, and execute the swing.

[0040] Furthermore, the calculation of Tv in step S3 is expressed by the following formula (9).

[0041] Tv=Tv0+dR*Ga+dF*(1-Ga) (9),

[0042] In equation (9), dF is the temperature deviation of the finishing mill inlet of the strip in the previous rolling process, and dF = the measured temperature T of the finishing mill in the previous rolling process. J - Target temperature T at the end of the finishing mill J0 Target temperature T at the inlet of the finishing mill J0 It is a requirement of the rolling production line.

[0043] Furthermore, in step S6, the delayed unwinding time DelayT of the hot roll box is calculated according to the following formula (10).

[0044] DelayT=DelayT0+dR*G1+dF*(1-G1) (10)

[0045] In equation (10), dF is the temperature deviation of the finishing mill inlet of the strip in the previous rolling process, and dF = the measured temperature T of the finishing mill in the previous rolling process. J - Target temperature T at the end of the finishing mill J0 Target temperature T at the inlet of the finishing mill J0 It is a requirement of the rolling production line.

[0046] Furthermore, as is known, W in equation (2) is calculated according to equation (11).

[0047]

[0048] In equation (11), ρ is the density coefficient of the strip, Cp is the specific heat coefficient of the strip, V is the volume of the strip, and Q is the heat lost by radiation of the strip, calculated according to equation (12).

[0049] Q=ε*A*σ(T 环境 -T 入口 (12)

[0050] In equation (12), ε is the thermal emissivity coefficient, A is the emissivity coefficient, σ is the Stefan-Boltzmann constant, and T 环境 It refers to the ambient temperature.

[0051] Furthermore, in equation (3), G is 0.05-0.15, in equation (5), DelayT0 is 10-20 seconds and G1 is 0.8-0.95, in equation (8), Ga is 0.65-0.75, and the initial value of the oscillation time is 0-180 seconds. Attached Figure Description

[0052] Figure 1 This is a layout diagram of the rolling production line equipment involved in the method for simultaneously controlling the roughing exit temperature and finishing entry temperature of IF steel rib strip of the present invention. Detailed Implementation

[0053] Example 1

[0054] This embodiment describes a method for simultaneously controlling the roughing mill exit temperature and finishing mill inlet temperature of IF steel ribbed strip. It relates to the Meigang 1422 hot rolling production line. The specifications of a certain IF steel ribbed strip are shown in Table 1 below. The rolling production line has two roughing mill stations, R1 and R2. An existing temperature calculation model for the rolling production line is available.

[0055] Table 1

[0056]

[0057] The specific steps are as follows:

[0058] S1. Set up a roughing rolling mode with one pass for R1 and seven passes for R2, with the last pass of R2 (the seventh pass) skipped. Set the swing zone between the R1 and R2 mills, and start calculating the swing time and swinging after the R2 mill completes its sixth pass, as shown. Figure 1 As shown.

[0059] S2. Read the existing temperature calculation model of the rolling production line and calculate the inlet temperature T of the strip in the swinging region in the sixth pass of R2. 入口 It is 1040℃;

[0060] S3. Calculate the exit temperature T1 of the strip at R2 using the following formula (1) iteratively.

[0061] T1 = T_inlet - T_temperature drop (1),

[0062] In equation (1), T1 is the exit temperature of the strip at R2 calculated iteratively, and T_temperature drop is the temperature drop of the strip from the inlet to the outlet of the pre-R2 swing zone.

[0063] Temperature drop T = W * t1 (2),

[0064] In equation (2), W is the temperature drop of the strip from the inlet to the outlet of R2 in a fixed unit time, calculated by the existing temperature calculation model of the rolling production line. t1 is the oscillation time calculated in the current iteration, and the iterative calculation of t1 is expressed as in equation (3).

[0065] t1=t10+(T10-T0)*G, (3),

[0066] In equation (3), T0 is the target exit temperature of the roughing mill R2 specified for production, G is a coefficient in seconds / ℃, which is generally taken as 0.1; t10 is the oscillation time calculated in the previous iteration.

[0067] As is known, the existing temperature calculation model for rolling production lines calculates W according to the following formula (11).

[0068]

[0069] In equation (11), ρ is the density coefficient of the strip, Cp is the specific heat coefficient of the strip, V is the volume of the strip, and Q is the heat lost by radiation from the strip. As known, the temperature calculation model of the production line calculates Q according to the following equation (12).

[0070] Q=ε*A*σ(T 环境 -T 入口 (12)

[0071] In equation (12), ε is the thermal emissivity coefficient, A is the emissivity coefficient, σ is the Stefan-Boltzmann constant, and T 环境 It refers to the ambient temperature.

[0072] In this embodiment, W = 0.895℃ / second is calculated using the existing temperature calculation model of the rolling production line.

[0073] S4. Compare T1 calculated in each iteration with T0.

[0074] If |T1-T0|≥1, then repeat step S3;

[0075] If |T1-T0| < 1, then stop calculating the swing times t1 and T1, output the currently calculated swing time t1 as the time when the strip enters the swing, and execute the swing.

[0076] The following is a detailed explanation of steps S3 and S4. In this embodiment, the temperature drop T and T1 are calculated iteratively starting from the initial value of the oscillation time (0) as follows:

[0077] First calculation

[0078] The initial swing time = 0 seconds.

[0079] Temperature drop T = W * t1 = 0

[0080] T1 = T_inlet = 1040℃

[0081] Since 1040 is relatively large compared to 860, i.e., |1040-860|≥1, we continue the iterative calculation.

[0082] Second calculation

[0083] The previous iteration calculated the oscillation time t10 = the initial oscillation time = 0 seconds.

[0084] The oscillation time calculated in this iteration is t1 = 0 + (1040 - 860) * 0.1 = 18 seconds.

[0085] Temperature drop T = W * t1 = 0.895 * 18 = 16.11℃

[0086] T1 = T_inlet - T_temperature drop = 1040 - 16.11 = 1023.89℃

[0087] Since 1023.89 is relatively large compared to 860, i.e., |1023.89-860|≥1, we continue the iterative calculation.

[0088] Third calculation

[0089] The previous iteration calculated the oscillation time t10 = 18 seconds.

[0090] The oscillation time calculated in this iteration is t1 = 18 + (1023.89 - 860) * 0.1 = 34.39 seconds.

[0091] Temperature drop T = W * t1 = 0.895 * 34.39 ≈ 30.78℃

[0092] T1 = T_inlet - T_temperature drop = 1040 - 30.78 = 1009.22℃

[0093] Since 1009.22 is relatively large compared to 860, i.e., |1009.22-860|≥1, the iterative calculation continues;

[0094] Fourth calculation

[0095] The previous iteration calculated the oscillation time t10 = 34.39 seconds.

[0096] The oscillation time calculated in this iteration is t1 = 34.39 + (1009.22 - 860) * 0.1 = 49.31 seconds.

[0097] Temperature drop T = W * t1 = 0.895 * 49.31 ≈ 44.13℃

[0098] T1 = T_inlet - T_temperature drop = 1040 - 44.13 = 995.87℃

[0099] Since 995.87 is significantly different from 860, i.e., |995.87-860| ≥ 1, the iterative calculation continues. Because subsequent iterative calculations are identical to the above, a detailed description is omitted. All iterative calculation results are shown in Table 2 below. Until the fifty-seventh iteration, the current oscillation time t1 = 200.06 seconds ≈ 200 seconds, T1 = 860.94℃. Since |860.94-860| < 1 at this point, the calculation stops, and the currently calculated oscillation time of 200 seconds is output as the time for the strip to enter the oscillation, and the oscillation is executed.

[0100] Table 2

[0101]

[0102]

[0103]

[0104] S5. Calculate the temperature deviation dR at the exit of the roughing mill of the previous rolled strip according to the following formula (4).

[0105] dR=T R2 -T0 (4),

[0106] In equation (4), T R2 T0 is the measured roughing mill exit temperature of the previously rolled strip, and T0 is the target roughing mill exit temperature required for production; in this embodiment, T R2 The measured temperature is 867℃, therefore dR = 867 - 860 = 7℃

[0107] S6. Calculate the delayed unwinding time of the hot roll box according to the following formula (5): DelayT

[0108] DelayT=DelayT0+dR*G1 (5)

[0109] In equation (5), DelayT0 is the initial value of the hot roll box delay unwinding time, which is generally taken as 15 seconds, and G1 is a constant, which is generally taken as 0.9.

[0110] DelayT = 15 + 7 * 0.9 = 21.3 seconds

[0111] S7. Control the hot roll box to unwind for a delay of 21.3 seconds according to the calculated hot roll box delay unwinding time DelayT.

[0112] Example 2

[0113] This embodiment is a further improvement based on Embodiment 1. The difference from Embodiment 1 is that the iterative calculation of t1 in step S3 is expressed as follows (6):

[0114] t1=t10+(T10-T)*G, (6)

[0115] In equation (6), T is the roughing mill correction target exit temperature, which is corrected based on the measured roughing mill exit temperature and is calculated according to the following equation (7).

[0116] T = T0 - Tv (7),

[0117] In equation (7), Tv is the correction value for the target exit temperature of the roughing mill for the current rolled strip, and its calculation is expressed as in equation (8).

[0118] Tv=Tv0+dR*Ga (8),

[0119] In equation (8), Tv0 is the correction value of the roughing target exit temperature of the strip in the previous rolling process; Ga is a constant, generally taken as 0.7;

[0120] After calculating Tv and T, the temperature drop and T1 are calculated iteratively from the initial value according to the oscillation time.

[0121] In step S4, T1 calculated in each iteration is compared with T.

[0122] If |T1-T| ≥ 1, then repeat step S3;

[0123] If |T1-T| < 1, then stop the calculation, output the currently calculated swing time t1 as the time when the strip enters the swing, and execute the swing.

[0124] Since the target exit temperature T0 of the roughing mill is corrected to the corrected target exit temperature T of the roughing mill, the following is a detailed explanation of the changes in steps S3 and S4 of this embodiment. After calculating Tv and T, the temperature drop T1 and T1 are calculated iteratively starting from 0 according to the initial value of the oscillation time as follows:

[0125] 1) Calculation of Tv and T

[0126] In this embodiment, the measured roughing mill exit temperature T of the previously rolled strip is read. R2 =867℃, initial roughing mill exit temperature correction value Tv0 = 0, Ga is taken as 0.7, then

[0127] dR = 867 - 860 = 7℃

[0128] Tv = 0 + dR * Ga = 7 * 0.7 = 4.9℃

[0129] T=T0-Tv=860-4.9=855.1℃

[0130] 2) Calculation of swing time

[0131] First calculation

[0132] If the initial swing time is 0 seconds, then

[0133] Temperature drop T = W * t1 = 0

[0134] T1 = T_inlet = 1040℃

[0135] Second calculation

[0136] The previous iteration calculated the oscillation time t10 = the initial oscillation time = 0 seconds. The previous iteration calculated the strip exit temperature at R2 as T10 = 1040℃, and W = 0.895℃ / second.

[0137] The duration of this oscillation is t1 = 0 + (1040 - 855.1) * 0.1 = 18.49 seconds.

[0138] Temperature drop T = W * t1 = 0.895 * 18.49 ≈ 16.55℃

[0139] T1 = T_inlet - T_temperature drop = 1040 - 16.55 = 1023.45℃

[0140] Since 1023.45 is relatively large compared to 855.1, i.e., |1023.45-855.1|≥1, the iterative calculation continues;

[0141] Third calculation

[0142] The previous iteration calculated the oscillation time t10 = 18.49 seconds, and the previous iteration calculated the strip exit temperature at R2 to be T10 = 1023.45℃. Therefore...

[0143] The oscillation time calculated in this iteration is t1 = 18.49 + (1023.45 - 855.1) * 0.1 = 35.325 seconds.

[0144] Temperature drop T = W * t1 = 0.895 * 35.325 ≈ 31.62℃

[0145] T1 = T_inlet - T_temperature drop = 1040 - 31.62 = 1008.38℃

[0146] Since 1008.38 is relatively large compared to 855.1, i.e., |1008.38-855.1|≥1, the iterative calculation continues;

[0147] Fourth calculation

[0148] The previous iteration calculated the oscillation time t10 = 35.325 seconds, and the previous iteration calculated the strip exit temperature at R2 T10 = 1008.38℃. Therefore...

[0149] The oscillation time calculated in this iteration is t1 = 35.325 + (1008.38 - 855.1) * 0.1 = 50.653 seconds.

[0150] Temperature drop T = W * t1 = 0.895 * 50.653 ≈ 45.33℃

[0151] T1 = T_inlet - T_temperature drop = 1040℃ - 45.33 = 994.67℃

[0152] Since 994.67 is significantly smaller than 855.1 (i.e., |994.67 - 855.1| ≥ 1), the iterative calculation continues. Because subsequent iterative calculations are identical to the above, a detailed description is omitted. All iterative calculation results are shown in Table 3. Until the forty-seventh iteration, the current swing time t1 = 195.76 seconds ≈ 196 seconds, T1 = 856.03℃, and T = 855.1℃. Since |856.03 - 855.1| < 1 at this point, the calculation of swing times t1 and T1 is stopped. The currently calculated swing time of 196 seconds is output as the time for the strip to enter the swing phase, and the swing is executed.

[0153] Table 3

[0154]

[0155]

[0156] The iterative calculations of the oscillation time and the roughing mill (R2) exit temperature described above started from an initial oscillation time of 0 and were performed 46 times to determine the final oscillation time. The iterative process is lengthy. To simplify the calculations, it is practically possible to start the iterations with an initial oscillation time of 100 or 150 seconds, thus reducing the number of iterations. The initial oscillation time of 100 or 150 seconds is based on empirical values.

[0157] Example 3

[0158] This embodiment is a further improvement on the basis of embodiment two. The difference is that, except for the fact that it is the same as embodiment one, the calculation of Tv in step S3 is expressed by the following formula (9).

[0159] Tv=Tv0+dR*Ga+dF*(1-Ga) (9),

[0160] In equation (9), dF is the temperature deviation of the finishing mill inlet of the strip in the previous rolling process, and dF = the measured temperature T of the finishing mill in the previous rolling process.J - Target temperature T at the end of the finishing mill J0 Target temperature T at the inlet of the finishing mill J0 This is a requirement of the rolling production line; in this embodiment, T... J0 It is 840℃.

[0161] Because the change in Tv calculation leads to corresponding changes in steps 3 and S4, the following is a detailed explanation of the changed steps S3 and S4 in this embodiment. After calculating Tv and T, the temperature drop and T1 are calculated iteratively starting from 100 according to the initial value of the oscillation time as follows:

[0162] 1) Calculation of Tv and T

[0163] In this embodiment, the measured roughing mill exit temperature T of the previously rolled strip is read. R2 =867℃, then dR = 867 - 860 = 7℃,

[0164] In this embodiment, the measured finishing mill inlet temperature T of the previously rolled strip is read. J =845℃, then dF = 845 - 840 = 5℃,

[0165] The initial roughing mill exit temperature correction value is Tv0 = 0, and Ga is taken as 0.7.

[0166] Tv=0+dR*Ga+dF*(1-Ga)=7*0.7+5*0.3=6.4℃,

[0167] T=T0-Tv=860-6.4=853.6℃

[0168] 2) Calculation of strip oscillation time

[0169] First calculation

[0170] If the initial swing time is 100 seconds, then...

[0171] Temperature drop T = W * t1 = 0.895 * 100 = 89.5℃

[0172] T1 = T_inlet - T_temperature drop = 1040 - 89.5 = 950.5℃

[0173] Since 950.5 is relatively large compared to 853.6, i.e., |950.5-853.6|≥1, the iterative calculation continues;

[0174] Second calculation

[0175] The previous iteration calculated the oscillation time t10 = the initial oscillation time = 100 seconds, and the previous iteration calculated the strip exit temperature at R2 as T10 = 950.5℃. Therefore...

[0176] The oscillation time in this iteration is t1 = 100 + (950.5 - 853.6) * 0.1 = 109.69 seconds.

[0177] Temperature drop T = W * t1 = 0.895 * 109.69 ≈ 98.17℃

[0178] T1 = T_inlet - T_temperature drop = 1040 - 98.17 = 941.83℃

[0179] Since 941.83 is relatively large compared to 853.6, i.e., |941.83-853.6|≥1, the iterative calculation continues.

[0180] Third calculation

[0181] The previous iteration calculated the oscillation time t10 = 109.69 seconds, and the previous iteration calculated the strip exit temperature at R2 to be T10 = 941.83℃. Therefore...

[0182] The oscillation time calculated in this iteration is t1 = 109.69 + (941.83 - 853.6) * 0.1 = 118.513 seconds.

[0183] Temperature drop T = W * t1 = 0.895 * 118.513 ≈ 106.07℃

[0184] T1 = T_inlet - T_temperature drop = 1040 - 106.07 = 933.93℃

[0185] Since 933.93 is relatively large compared to 853.6, i.e., |933.93-853.6|≥1, the iterative calculation continues;

[0186] Fourth calculation

[0187] The previous iteration calculated the oscillation time t10 = 118.513 seconds, and the previous iteration calculated the strip exit temperature at R2 T10 = 933.93℃. Therefore...

[0188] The oscillation time calculated in this iteration is t1 = 118.513 + (933.93 - 853.6) * 0.1 ≈ 126.55 seconds.

[0189] Temperature drop T = W * t1 = 0.895 * 126.55 ≈ 113.26℃

[0190] T1 = T_inlet - T_temperature drop = 1040℃ - 113.26 = 926.74℃

[0191] Since 926.74 is significantly larger than 853.6 (i.e., |926.74-853.6| ≥ 1), the iterative calculation continues. Because subsequent iterative calculations are identical to the above, a detailed description is omitted. All iterative calculation results are shown in Table 4. Until the 39th iteration, the current swing time t1 = 198.6 seconds ≈ 199 seconds, T1 = 853.28℃, and T = 853.6℃. Since |853.28-853.6| < 1 at this point, the calculation of swing times t1 and T1 is stopped. The currently calculated swing time of 199 seconds is output as the time for the strip to enter the swing phase, and the swing is executed.

[0192] Table 4

[0193]

[0194]

[0195] Example 4

[0196] This embodiment is a further improvement based on Embodiment 1, Embodiment 2, or Embodiment 3. The difference from Embodiment 1, Embodiment 2, or Embodiment 3 is that: in step S6, the hot roll box delay unwinding time DelayT is calculated according to the following formula (10).

[0197] DelayT=DelayT0+dR*G1+dF*(1-G1) (10)

[0198] In equation (10), dF is the temperature deviation of the finishing mill inlet of the strip in the previous rolling process, and dF = the measured temperature T of the finishing mill in the previous rolling process. J - Target temperature T at the end of the finishing mill J0 Target temperature T at the inlet of the finishing mill J0 It is a requirement of the rolling production line.

[0199] In this embodiment, the measured finishing mill inlet temperature T of the previously rolled strip is read. J It is 842℃, the target temperature T at the entry point of the finishing mill. J0 The temperature is 840℃. The previous strip roughing exit temperature deviation dR remains unchanged at 7℃. DelayT0 is set to 16 seconds, and G1 is set to 0.85.

[0200] dF = 842 = -840 = 2℃

[0201] DelayT=16+7*0.85+2*0.15=22.25 seconds.

[0202] Therefore, in step S7, the hot roll box is controlled to unwind after a delay of 22.25 seconds.

[0203] The above description is only a preferred embodiment of the present invention, but the present invention is not limited thereto. For example, 1) G in formula (3) can be other values ​​within the range of 0.05-0.15; 2) DelayT0 in formula (5) can also be other values ​​within the range of 10-20 seconds, and G1 can also be other values ​​within the range of 0.8-0.95; 3) Ga in formula (8) can also be other values ​​within the range of 0.65-0.75; 4) The initial value of the oscillation time can be other values ​​within the range of 0-180 seconds. All equivalent substitutions or equivalent changes made to the concept and technical solutions of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for simultaneously controlling the exit temperature of the roughing mill and the inlet temperature of the finishing mill for IF steel rib strip, involving two roughing mill stations R1 and R2 in the rolling production line, a hot coil box, and an existing temperature calculation model for the rolling production line, characterized in that... Perform the following steps: S1. Set the roughing mode of one pass for R1 and seven passes for R2, and let the seventh pass of R2 pass empty. Set the swing zone between the R1 mill and the R2 mill, and enter the swing zone after the R2 mill completes the sixth pass to start calculating the swing time and swinging. S2. Read the temperature calculation model and calculate the inlet temperature T of the strip in the swing zone in the sixth pass of R2. 入口 ; S3. Calculate the exit temperature T1 of the strip at R2 using the following formula (1) iteratively. T1=T 入口 -T 温降 (1) In equation (1), T1 is the exit temperature of the strip at R2 calculated iteratively, and T 温降 It is the temperature drop of the strip from the inlet of the R2 pre-oscillation zone to the outlet of R2, calculated according to the following formula (2). T 温降 =W*t1 (2), In equation (2), W is the temperature drop per unit time of the strip from the inlet to the outlet of R2 in the swing zone before R2 calculated by the temperature calculation model, and t1 is the swing time calculated in the current iteration after iterative calculation. The iterative calculation of t1 is expressed as in equation (3). t1=t10+(T10-T0)*G, (3), In equation (3), T10 is the exit temperature of the strip at R2 calculated in the previous iteration, T0 is the target exit temperature of the roughing mill at R2 specified in production, G is a coefficient in seconds / ℃, and t10 is the oscillation time calculated in the previous iteration. Based on the calculation of the oscillation time, t1 and T are calculated iteratively starting from the initial value. 温降 and T1; S4. Compare T1 calculated in each iteration with T0. If |T1-T0|≥1, then repeat step S3; If |T1-T0| < 1, then stop the calculation, output the currently calculated swing time t1 as the time when the strip enters the swing and execute the swing; S5. Calculate the temperature deviation dR at the exit of the roughing mill of the previous strip according to the following formula (4). dR=T R2 -T0 (4), In equation (4), T R2 T0 is the measured roughing mill exit temperature of the previous rolled strip, and T0 is the target roughing mill exit temperature required for production. S6. Calculate the delayed unwinding time of the hot roll box according to the following formula (5): DelayT DelayT = DelayT0 + dR * G1 (5) In equation (5), DelayT0 is the initial value of the hot roll box delay unwinding time, and G1 is a constant; S7. Control the hot roll box to delay unwinding according to the calculated hot roll box delay unwinding time DelayT.

2. The method for simultaneously controlling the exit temperature of the roughing mill and the inlet temperature of the finishing mill for IF steel ribbed strip according to claim 1, characterized in that: In step S3, the iterative calculation of t1 is expressed by the following equation (6): t1=t10+(T10-T)*G, (6) In equation (6), T is the roughing mill correction target exit temperature, which is calculated according to the measured roughing mill exit temperature and is determined by the following equation (7). T = T0 - Tv (7), In equation (7), Tv is the correction value for the roughing target exit temperature of the current rolled strip, which is calculated and expressed in equation (8). Tv=Tv0+dR*Ga (8) In equation (8), Tv0 is the correction value of the target exit temperature of the previous rolled strip, Ga is a constant, dR is the deviation of the exit temperature of the previous rolled strip, and dR = the measured exit temperature of the previous rolled strip - the target exit temperature of the previous rolled strip T0. t1 and T are calculated iteratively from the initial value based on the oscillation time. 温降 and T1; In step S4, T1 calculated in each iteration is compared with T. If |T1-T| ≥ 1, then repeat step S3; If |T1-T| < 1, then stop the calculation, output the currently calculated swing time t1 as the time when the strip enters the swing, and execute the swing.

3. The method for simultaneously controlling the exit temperature of the roughing mill and the inlet temperature of the finishing mill for IF steel ribbed strip according to claim 2, characterized in that: The calculation of Tv in step S3 is expressed by the following formula (9). Tv=Tv0+dR*Ga+dF*(1-Ga) (9), In equation (9), dF is the temperature deviation of the finishing mill inlet of the strip in the previous rolling process, and dF = the measured temperature T of the finishing mill in the previous rolling process. J - Target temperature T at the end of the finishing mill J0 Target temperature T at the inlet of the finishing mill J0 It is a requirement of the rolling production line.

4. The method for simultaneously controlling the exit temperature of the roughing mill and the inlet temperature of the finishing mill for IF steel ribbed strip according to claim 1, 2, or 3, characterized in that: In step S6, the hot roll box delay unwinding time DelayT is calculated according to the following formula (10). DelayT=DelayT0+dR*G1+dF* (1- G1) (10) In equation (10), dF is the temperature deviation of the finishing mill inlet of the strip in the previous rolling process, and dF = the measured temperature T of the finishing mill in the previous rolling process. J - Target temperature T at the end of the finishing mill J0 Target temperature T at the inlet of the finishing mill J0 It is a requirement of the rolling production line.

5. The method for simultaneously controlling the exit temperature of the roughing mill and the inlet temperature of the finishing mill for IF steel ribbed strip according to claim 1, 2, or 3, characterized in that: The W is calculated according to the following formula (11), （11）, In equation (11), C is the density coefficient of the strip steel. p V is the specific heat coefficient of the strip, V is the volume of the strip, and Q is the heat lost by radiation from the strip, calculated according to the following formula (12). （12） In equation (12), A is the thermal emissivity coefficient, and A is the emissivity coefficient. It is the Stefan-Boltzmann constant. It refers to the ambient temperature.

6. The method for simultaneously controlling the exit temperature of the roughing mill and the inlet temperature of the finishing mill for IF steel ribbed strip according to claim 2 or 3, characterized in that: In equation (3), G is 0.05-0.15, in equation (5), DelayT0 is 10-20 seconds and G1 is 0.8-0.95, in equation (8), Ga is 0.65-0.75, and the initial value of the oscillation time is 0-180 seconds.

Images