A control method for solving the scratch at the tail of stainless steel rough rolling

Abstract

The present invention provides a control method for solving the problem of tail scratching in stainless steel rough rolling, including controlling the flat roll reduction amount in each pass of rough rolling and controlling the vertical roll speed in each pass of rough rolling. The control method of the present invention can avoid the phenomenon of tail turning up in the first and third passes of rough rolling of 430 steel grade, thereby avoiding tail scratching.

Description

Technical Field

[0001] The invention relates to the field of metallurgical science and technology, and in particular to a control method for solving the scratching of the tail of rough rolling of stainless steel. Background Art

[0002] Figure 1 The hot rolling line layout shown is a common hot rolling production line for producing 430 steel grades, which is specifically divided into furnace area, rough rolling area, finishing rolling area, and coiling area. When using this production line to rough roll 430 steel grades, tail scratches will occur.

[0003] The main production process of the hot rolling production line is that the slab is first heated in the heating furnace according to the temperature specified by the process, and then enters the rough rolling mill for rolling after being heated to the target temperature. The rough rolling vertical roll controls the width, and the flat roll controls the thickness. Reversible rolling is performed in the rough rolling mill, generally 5 to 7 times, with a minimum of 1 time and a maximum of 9 times. During the 1st, 3rd, 5th, and 7th odd-pass rolling, the vertical roll rolling is first used to control the width. After the head of the strip exits the vertical roll, it enters the flat roll. The flat roll rolling controls the thickness. During the rolling of the flat roll and the vertical roll, the exit speed of the vertical roll is the entrance speed of the flat roll. After the tail of the strip exits the vertical roll, the part between the flat roll and the vertical roll is only rolled by the flat roll to complete the rolling of this time; and during the 2nd, 4th, and 6th even-pass rolling, only flat roll rolling is performed, and the opening of the vertical roll is released and not controlled.

[0004] After the rough rolling mill, the strip reaches the preset target thickness, width and temperature. Then it enters the finishing mill for seven-stand flat roll continuous rolling to make the strip reach the preset target thickness and temperature. Finally, the strip is formed into a coil by the coiler.

[0005] 400 series stainless steel is a commonly used stainless steel variety, and 430 steel is the most important stainless steel variety of 400 series stainless steel. 430 stainless steel is rolled through hot rolling and then cold rolled in the cold rolling process before being delivered to users.

[0006] The most important quality characteristic of 430 stainless steel is the surface quality, among which surface scratch defect is the most influential defect of stainless steel for users. After the scratch defect occurs, the defective part must be cut off before circulation. If the entire length is scratched, the coil will be scrapped. During the rough rolling process of the hot rolling production line, the tail of the continuous casting billet is frequently scratched. In severe cases, more than 100 meters of the hot rolling finished strip needs to be cut off, which has a great impact on the 430 yield rate and logistics efficiency. Scratches such as Figure 2 shown.

[0007] Therefore, providing a control method for solving the scratches on the tail of stainless steel rough rolling is an urgent problem to be solved. Summary of the invention

[0008] In view of the above problems, the present invention provides a control method for solving the tail scratching in stainless steel rough rolling, which is a control method carried out by changing the flat roll load and the vertical roll speed, effectively eliminating the phenomenon of tail turning up, and thus preventing the tail scratching phenomenon.

[0009] The present invention achieves the above object through the following technical solutions:

[0010] A control method for solving the tail scratching in stainless steel rough rolling, including controlling the flat roll reduction amount of each pass in rough rolling and controlling the vertical roll speed of each pass in rough rolling;

[0011] The control of the flat roll reduction amount of each pass in rough rolling includes:

[0012] Determine the given initial reduction amount RA(i) of the i-th pass, where i is an integer from 1 to 5;

[0013] Calculate the given total reduction amount in rough rolling

[0014] Calculate the reduction ratio RR(i) of the i-th pass = RA(i) / RA_sum;

[0015] Calculate the actual total reduction amount RA_sum_act in rough rolling = slthc - barthc, where slthc represents the slab thickness and barthc represents the rough rolling target thickness;

[0016] Calculate the actual reduction amount RA_act(i) of the i-th pass = RA_sum_act × RR(i);

[0017] The control of the vertical roll speed of each pass in rough rolling includes:

[0018] Determine the rolling speed v(i) of the flat roll in the i-th pass;

[0019] Calculate the exit speed vexit(i) of the flat roll in the i-th pass = v(i) × forwardslip(i), where forwardslip(i) represents the front slip value of the i-th pass;

[0020] Calculate the entry speed venty(i) of the i-th pass = vexit(i) × exitthick(i) / entythick(i), where exitthick(i) represents the exit thickness of the i-th pass in mm and entythick(i) represents the entry thickness of the i-th pass in mm;

[0021] Calculate the vertical roll speed ve(i) of the i-th pass, where when i is 1, 3 or 5, ve(i) = venty(i), and when i is 2 or 4, ve(i) = vexit(i).

[0022] Optionally, the stainless steel is stainless steel of grade 430.

[0023] Optionally, the thickness of the slab of the stainless steel is 200 mm.

[0024] Optionally, RA_act(1) = RA(1) = 42.6 mm, RA_act(3) = RA(3) = 28.3 mm.

[0025] Optionally, the thickness of the slab of the stainless steel is 180 mm.

[0026] Optionally, RA_act(1) = RA(1) = 41.2 mm, RA_act(3) = RA(3) = 26.1 mm.

[0027] Optionally, controlling the flat roll reduction in each rough rolling pass includes:

[0028] Determining the given initial reductions RA(2), RA(4), and RA(5) for the 2nd, 4th, and 5th passes;

[0029] Calculating the total given rough rolling reduction RA1_sum = RA(2) + RA(4) + RA(5) for the 2nd, 4th, and 5th passes;

[0030] Calculating the reduction ratio RR(i) = RA(i) / RA1_sum for the 2nd, 4th, and 5th passes, where i is 2, 4, or 5;

[0031] Calculating the actual total rough rolling reduction RA_sum_act = slthc - barthc, where slthc represents the slab thickness and barthc represents the rough rolling target thickness;

[0032] Calculating the actual reduction RA_act(i) = RA1_sum_act × RR(i) for the 2nd, 4th, and 5th passes, where RA1_sum_act = RA_sum_act - RA(1) - RA(3).

[0033] Optionally, controlling the vertical roll speed in each rough rolling pass includes controlling the vertical roll speeds of the 1st and 3rd passes, where ve(i) = venty(i) × (1 - coff), where i is 1 or 3 and coff represents the vertical roll speed correction coefficient.

[0034] Optionally, the value of the vertical roll speed correction coefficient coff is:

[0035] Side pressure amount, unit: mm coff value <10 0.00 10～20 0.01 20～30 0.02 30～40 0.03 40～50 0.04 ≥50 0.05 。

[0036] Compared with the prior art, the method for solving the problem of tail scratching in rough rolling of stainless steel of the present invention has at least the following beneficial effects:

[0037] The control method of the present invention can effectively avoid the tail turning up phenomenon of 430 steel during the first and third rough rolling, thereby eliminating the tail scratch phenomenon, reducing the cutting length of each steel piece by 45 meters on average, and improving the yield rate by about 2%, with obvious economic benefits.

[0038] The control method of the present invention can play a very key role in improving the surface quality of 430 stainless steel, increasing the yield rate, etc., and can be promoted and applied to all 400 series stainless steel varieties, and has significant promotion and application value for hot rolling production lines in the same industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic diagram of the equipment involved in the hot rolling process, including: 1. Heating furnace, including 4 heating furnaces and 1 trolley furnace; 2. High-pressure water descaling box; 3. Roughing vertical roll mill (VE0); 4. Roughing flat roll mill (R0); 5. Insulation cover; 6. Drum-type head cutting flying shear; 7. Finishing mill stand (7 stands); 8. Convexity meter; 9. Width gauge; 10. Thickness gauge; 11. Straightness meter; 12. Laminar cooling; 13. Coiler.

[0040] Figure 2 Shows the scratches on the tail of 430 stainless steel.

[0041] Figure 3 It is a schematic diagram of the vertical roller structure, in which the H part represents the roller body.

[0042] Figure 4 The control process of rough rolling load and speed in 5-pass rolling of 430 stainless steel is shown.

[0043] Figure 5 The stainless steel tail obtained by the control method of Example 1 is shown. DETAILED DESCRIPTION

[0044] In order to fully understand the purpose, features and effects of the present invention, the present invention is described in detail through the following specific embodiments. Except for the following contents, the process method of the present invention adopts conventional methods or devices in the art. Unless otherwise specified, the following terms have the meanings commonly understood by those skilled in the art.

[0045] In order to solve the problem of tail scratches on 430 stainless steel, the inventor of the present invention conducted a systematic analysis based on the rolling site and found that the scratch defect was caused by the uneven deformation of the two sides (working side and transmission side) of the strip after the tail exits the vertical roll. After the tail of the strip turns up, it will rub against the upper edge of the vertical roll body, thus causing scratches. Figure 3 shown.

[0046] To solve the problem of the upward turning of the strip tail caused by uneven strip deformation and the resulting tail scratching, the present invention proposes a method of controlling by changing the flat roll load and using a micro-tension between the vertical roll and the flat roll, effectively eliminating the phenomenon of upward turning of the tail, thereby preventing the tail scratching phenomenon.

[0047] The overall technical concept of the present invention is to reduce the reduction of the flat roll in the pass where the tail turns upward, and at the same time, control is carried out through a micro-tension between the vertical roll and the flat roll. By changing the flat roll load distribution and calculating the vertical roll speed, the purpose of uniform tail deformation and difficult upward turning during 430 rolling is achieved, thereby effectively solving the problem of upward turning of the tail during 430 rolling and preventing tail scratching. 430 stainless steel is rolled in 5 passes during rough rolling. Therefore, the present invention mainly makes a creative design for the flat roll load distribution in 5 passes and the calculation of the vertical roll speed in the 1st and 3rd passes. The control process of the rough rolling load (i.e., the reduction of the flat roll) and speed is as Figure 4 shown.

[0048] The present invention provides a control method for solving the tail scratching in stainless steel rough rolling, including controlling the reduction of the flat roll in each pass of rough rolling and controlling the speed of the vertical roll in each pass of rough rolling.

[0049] Specifically, the steps of controlling the reduction of the flat roll in each pass of the control method of the present invention include:

[0050] Step S1101, determine the given initial reduction RA(i) of the i-th pass, where i is an integer from 1 to 5. The given initial reduction of each pass of the flat roll generally follows the principle of gradually decreasing according to the pass, and this reduction method is named RA.

[0051] For example, the given initial reduction of each pass of the flat roll of 430 stainless steel is as follows:

[0052]

[0053] Step S1102, calculate the total given reduction in rough rolling For example, RA_sum = RA(1) + RA(2) + RA(3) +

[0054] RA(4) + RA(5) = 47.8 + 45.6 + 33.1 + 24.9 + 16.7 = 168.1 (mm)

[0055] Step S1103, calculate the reduction ratio RR(i) of the i-th pass, that is, the ratio of the given initial reduction of each pass to the total given reduction in rough rolling. Specifically, RR(i) = RA(i) / RA_sum.

[0056] For example, the reduction ratios of each pass of 430 stainless steel are as follows:

[0057]

[0058] Step S1104: Calculate the actual total reduction of rough rolling RA_sum_act = slthc - barthc, where slthc represents the slab thickness and barthc represents the target thickness of rough rolling.

[0059] For example, for a 430 stainless steel slab with a thickness of 200 mm and a target thickness of rough rolling of 35 mm, then the actual total reduction of rough rolling RA_sum_act = slthc - barthc = 200 - 35 = 165 (mm).

[0060] Step S1105: Calculate the actual reduction of the i-th pass RA_act(i) = RA_sum_act × RR(i).

[0061] For example, for a 430 stainless steel slab with a thickness of slthc of 200 mm, a target thickness of rough rolling of barthc of 35 mm, and an actual total reduction of rough rolling of RA_sum_act of 165 mm, then the actual reduction of each pass, the actual entry thickness and exit thickness of each pass are as follows:

[0062]

[0063] By means of the above process, the control of the flat roll reduction of each pass in rough rolling can be achieved.

[0064] Specifically, the steps of controlling the vertical roll speed of each pass in rough rolling of the control method of the present invention include:

[0065] Step S1201: Determine the rolling speed v(i) of the i-th pass of the flat roll.

[0066] Among them, the values are taken according to the table model as follows:

[0067]

[0068] Among them, the above odd passes (the 1st, 3rd, and 5th passes) are forward rolling, and the speed is positive; the even passes (the 2nd and 4th passes) are reverse rolling, and the speed is negative.

[0069] Step S1202: Calculate the exit speed vexit(i) of the i-th pass of the flat roll = v(i) × forwardslip(i), where forwardslip(i) represents the forward slip value of the i-th pass, and its specific calculation steps are as follows:

[0070] Step 1: Calculate the intermediate variable factor of forward slip.

[0071] xh_kapa(i) = sqrt(((gr(WRU)+gr(WRL)) / 2.0) / entythick(i))

[0072] Among them, xh_kapa(i) represents the front slip intermediate variable factor, sqrt represents the square root operation, gr(WRU) represents the upper roll radius of the work roll, gr(WRL) represents the lower roll radius of the work roll, and entythick(i) represents the entrance thickness at the i-th pass.

[0073] Step 2: Calculate the front slip factor related to thickness.

[0074] xth_kapa(i) = ((((0.00000471 × xh_kapa(i) - 0.00025518) × xh_kapa(i) + 0.0053778) × xh_kapa(i) - 0.056242) × xh_kapa(i) + 0.31057) × xh_kapa(i) + 0.21879

[0075] Among them, xth_kapa(i) represents the front slip factor related to thickness.

[0076] Step 3: Calculate the front slip factor related to the reduction rate.

[0077] xeps_kapa(i) = ((((7.6896 × eps(i) - 10.841) × eps(i) + 4.9006) × eps(i) - 0.8848) × eps(i) + 0.3318) × eps(i) + 0.0

[0078] Among them, xeps_kapa(i) represents the front slip factor related to the reduction rate, and eps(i) represents the thickness reduction rate at the i-th pass, and its calculation method is as follows:

[0079] eps(i) = (entythick(i) - exitthick(i)) / entythick(i)

[0080] Step 4: Calculate the front slip value.

[0081] forwardslip(i) = xth_kapa(i) × xeps_kapa(i) + 1

[0082] Among them, forwardslip(i) represents the front slip value at the i-th pass, xth_kapa(i) represents the front slip factor related to thickness, and xeps_kapa(i) represents the front slip factor related to the reduction rate.

[0083] Step S1203: Calculate the inlet speed venty(i) of the i-th pass as venty(i) = vexit(i) × exitthick(i) / entythick(i), where exitthick(i) represents the exit thickness of the i-th pass in mm, and entythick(i) represents the inlet thickness of the i-th pass in mm.

[0084] Step S1204: Calculate the vertical roll speed ve(i) of the i-th pass. Specifically, there are two cases for odd and even passes. When it is an odd pass, i.e., i is 1, 3, or 5, ve(i) = venty(i); when it is an even pass, i.e., i is 2 or 4, ve(i) = vexit(i).

[0085] Based on the above research, the inventor conducted repeated tests and summaries for two specific specifications of the 430 steel grade, namely slab thicknesses of 200 mm and 180 mm, and continuously reduced the reduction amounts in the first and third passes, and obtained the following conclusion: When the reduction amounts in the first and third passes take the following reduction amounts, the incidence of tail upward turning is the smallest.

[0086] Slab thickness RA(1) RA(3) 200mm 42.6mm 28.3mm 180mm 41.2mm 26.1mm

[0087] As a preferred specific implementation manner, for 430 stainless steel with slab thicknesses of 200 mm and 180 mm, the present invention proposes a control method for solving the problem of tail scratching in rough rolling of stainless steel, including controlling the flat roll reduction amount in each pass of rough rolling and controlling the vertical roll speed in each pass of rough rolling.

[0088] In the step of controlling the flat roll reduction amount in each pass of rough rolling, a control method with a fixed reduction amount is adopted for the first and third passes, so that the actual reduction amounts in the first and third passes are equal to the given initial reduction amounts, specifically, select RA_act(1) = RA(1), RA_act(3) = RA(3). It should be noted that in the present invention, the above control method with a fixed reduction amount is named RAA. Therefore, when the control method with a fixed reduction amount is adopted for the first and third passes, the given initial reduction amounts can also be expressed as RAA(1) and RAA(3), that is, RA(1) = RAA(1), RA(3) = RAA(3).

[0089] In the step of controlling the vertical roll speed in each pass of rough rolling, mainly for the first and third passes, that is, the passes where the tail turns upward, a micro-tension control is established between the flat roll and the vertical roll.

[0090] Specifically, the step of controlling the flat roll reduction amount in each pass of the control method of the present invention includes:

[0091] Step S2101: Fix the given initial reduction ratios for the 1st and 3rd passes as RA(1) = RAA(1) and RA(3) = RAA(3), and determine the given initial reduction ratios RA(2), RA(4), and RA(5) for the 2nd, 4th, and 5th passes.

[0092] Among them, for the flat rolls of 430 stainless steel with a slab thickness of 200 mm, the given initial reduction ratios for each pass are as follows (taking a slab thickness of 200 mm as an example for illustration, the control processes for slab thicknesses of 180 mm and 200 mm are exactly the same):

[0093]

[0094] Step S2102: Calculate the total roughing reduction ratio RA1_sum = RA(2) + RA(4) + RA(5) for the 2nd, 4th, and 5th passes.

[0095] Since the 1st pass and the 3rd pass adopt the method of fixed reduction ratio, that is, the initial reduction ratio is the final reduction ratio, when calculating the proportional change of the reduction ratio to reach the target thickness, it is only executed for the passes other than the 1st and 3rd passes.

[0096] For example, RA1_sum = RA(2) + RA(4) + RA(5) = 45.6 + 24.9 + 16.7 = 87.2 (mm)

[0097] Step S2103: Calculate the reduction ratio proportion RR(i) = RA(i) / RA1_sum for the 2nd, 4th, and 5th passes, where i is 2, 4, or 5. That is, only calculate the proportion of the given initial reduction ratio of each pass in the RA method to the total given reduction ratio in the RA method.

[0098] For example:

[0099]

[0100] Step S2104: Calculate the actual total roughing reduction ratio RA_sum_act = slthc - barthc, where slthc represents the slab thickness and barthc represents the roughing target thickness.

[0101] For example, for a 430 stainless steel slab with a thickness of 200 mm and a roughing target thickness of 35 mm, then the actual total roughing reduction ratio RA_sum_act = slthc - barthc = 200 - 35 = 165 (mm).

[0102] Step S2105: Calculate the actual reduction ratio for each pass.

[0103] Since the first and third passes adopt the fixed reduction ratio control method, that is, the RAA method, therefore, the initial reduction ratios of the first and third passes are the final actual reduction ratios, that is

[0104] RA_act(1) = RAA(1)

[0105] RA_act(3) = RAA(3)

[0106] For example, for 430 stainless steel with a slab thickness of 200 mm, RA_act(1) = RAA(1) = 42.6 mm, and RA_act(3) = RAA(3) = 28.3 mm.

[0107] Then calculate the actual total reduction except for the first and third passes, that is, the actual total reduction in the RA method. Specifically, calculate the actual reduction RA_act(i) = RA1_sum_act × RR(i) for the 2nd, 4th, and 5th passes, where RA1_sum_act = RA_sum_act - RA(1) - RA(3).

[0108] For example, for 430 stainless steel with a slab thickness of 200 mm, RA1_sum_act = RA_sum_act - RA(1) - RA(3) = 165 - 42.6 - 28.3 = 94.1 (mm).

[0109] The actual reduction in each pass, the actual entry thickness, and the exit thickness in each pass are as follows:

[0110]

[0111] Through the above process, the optimal control of the flat roll reduction in each roughing pass can be achieved.

[0112] Specifically, the steps of controlling the vertical roll speed in each roughing pass of the control method of the present invention include:

[0113] Step S2201: Determine the rolling speed v(i) of the i-th pass of the flat roll.

[0114] Step S2202: Calculate the exit speed vexit(i) of the i-th pass of the flat roll = v(i) × forwardslip(i), where forwardslip(i) represents the forward slip value of the i-th pass and is calculated based on the entry thickness, thickness reduction rate, and roll diameter. The specific calculation steps are as follows:

[0115] Step 1: Calculate the intermediate variable factor of the forward slip.

[0116] xh_kapa(i) = sqrt(((gr(WRU) + gr(WRL)) / 2.0) / entythick(i))

[0117] Among them, xh_kapa(i) represents the front slip intermediate variable factor, sqrt represents the square root operation, gr(WRU) represents the radius of the upper work roll, gr(WRL) represents the radius of the lower work roll, and entythick(i) represents the entrance thickness at the i-th pass.

[0118] Step 2: Calculate the front slip factor related to thickness.

[0119] xth_kapa(i) = ((((0.00000471 × xh_kapa(i) - 0.00025518) × xh_kapa(i) + 0.0053778) × xh_kapa(i) - 0.056242) × xh_kapa(i) + 0.31057) × xh_kapa(i) + 0.21879

[0120] Among them, xth_kapa(i) represents the front slip factor related to thickness.

[0121] Step 3: Calculate the front slip factor related to the reduction rate.

[0122] xeps_kapa(i) = ((((7.6896 × eps(i) - 10.841) × eps(i) + 4.9006) × eps(i) - 0.8848) × eps(i) + 0.3318) × eps(i) + 0.0

[0123] Among them, xeps_kapa(i) represents the front slip factor related to the reduction rate, and eps(i) represents the thickness reduction rate at the i-th pass. The calculation method is as follows:

[0124] eps(i) = (entythick(i) - exitthick(i)) / entythick(i)

[0125] Step 4: Calculate the front slip value.

[0126] forwardslip(i) = xth_kapa(i) × xeps_kapa(i) + 1

[0127] Among them, forwardslip(i) represents the front slip value at the i-th pass, xth_kapa(i) represents the front slip factor related to thickness, and xeps_kapa(i) represents the front slip factor related to the reduction rate.

[0128] Step S2203: Calculate the inlet speed venty(i) of the i-th pass as venty(i) = vexit(i) × exitthick(i) / entythick(i), where exitthick(i) represents the exit thickness of the i-th pass in mm, and entythick(i) represents the inlet thickness of the i-th pass in mm.

[0129] Step S1204: Calculate the vertical roll speed ve(i) of the i-th pass.

[0130] When i is 1 or 3, ve(i) = venty(i) × (1 - coff), where coff represents the vertical roll speed correction coefficient, which is mainly related to the side pressure of the vertical roll. The greater the side pressure, the greater the value of coff; the smaller the side pressure, the smaller the value of coff. The value of coff is obtained based on experience and continuous experiments, as follows:

[0131] Side pressure amount (mm) coff value <10 0.00 10 - 20, that is, 10 ≤ side pressure amount < 20 0.01 20 - 30, that is, 20 ≤ side pressure amount < 30 0.02 30 - 40, that is, 30 ≤ side pressure amount < 40 0.03 40 - 50, that is, 40 ≤ side pressure amount < 50 0.04 ≥50 0.05

[0132] When i is 5, ve(i) = venty(i).

[0133] When i is 2 or 4, ve(i) = vexit(i).

[0134] By adopting the above control method, the phenomenon of the tail turning up during the first and third rough rolling passes of the 430 steel grade disappears, the phenomenon of tail scratching does not occur, and it can be further extended to other stainless steel grades.

[0135] Embodiment

[0136] The present invention will be further described below by way of embodiments, but the present invention is not limited to the scope of the described embodiments. For the experimental methods without specific conditions in the following embodiments, they are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0137] Embodiment 1:

[0138] This embodiment rolls 430 stainless steel, coil number: 924671301. The billet thickness is 200 mm, and the target thickness after rough rolling is 35 mm; the billet width is 1235 mm, and the target width of the finished strip is 1260 mm.

[0139] 1. Calculation of the rough rolling flat roll reduction

[0140] The steps for calculating the reduction are as follows:

[0141] 1) The RAA method is adopted for the reduction of the flat roll in the first and third passes, and the RA method is adopted for other passes. The initial reduction of each pass is:

[0142]

[0143] 2) Calculate the total reduction given in rough rolling:

[0144] Since the first pass and the third pass adopt the method of fixed reduction, when calculating the equal-proportion change of the reduction to reach the target thickness, it is only executed for the passes other than the first and third passes.

[0145] The total reduction of other passes, that is, the given total reduction in the RA mode, is

[0146] RA1_sum = RA(2) + RA(4) + RA(5) = 45.6 + 24.9 + 16.7 = 87.2 (mm)

[0147] 3) Calculate the reduction ratio of each pass for the passes other than the first and third passes, that is, the ratio of the given initial reduction of each pass in the RA mode to the given total reduction in the RA mode. The reduction ratio of each pass RR(i) is:

[0148] RR(i) = RA(i) / RA1_sum

[0149] The specific values obtained are:

[0150]

[0151] 4) Calculate the actual total reduction in rough rolling:

[0152] RA_sum_act = slthc - barthc = 200 - 35 = 165 (mm)

[0153] 5) Calculate the actual reduction of each pass. The method is:

[0154] Since the first and third passes adopt the fixed reduction control method, that is, the RAA mode, therefore, the initial reduction of the first and third passes is the final actual reduction, that is

[0155] RA_act(1) = RAA(1) = 42.6 mm

[0156] RA_act(3) = RAA(3) = 28.3 mm

[0157] Then calculate the actual total reduction for the passes other than the first and third passes, that is, the actual total reduction in the RA mode. It is obtained that:

[0158] RA1_sum_act = RA_sum_act – RAA(1) - RAA(3) = 165 - 42.6 - 28.3 = 94.1 (mm)

[0159] Calculate the actual reduction of each pass in the RA mode:

[0160] RA_act(2) = RA1_sum_act × RR(2) = 94.1 × 52.29% = 49.208 (mm)

[0161] RA_act(4) = RA1_sum_act × RR(4) = 94.1 × 28.56% = 26.870 (mm)

[0162] RA_act(5) = RA1_sum_act × RR(5) = 94.1 × 19.15% = 18.021 (mm)

[0163] The actual reduction per pass, the actual entry thickness per pass, and the exit thickness per pass are shown in the following table.

[0164]

[0165] 2. Calculation of vertical roll speed

[0166] 1) The rolling speeds of the horizontal rolls for each pass are as follows:

[0167]

[0168] 2) Calculation of the forward slip values for each pass of the roughing horizontal rolls:

[0169] Based on the entry thickness and exit thickness of each pass calculated above, and then according to the formula eps(i) = (entythick(i) - exitthick(i)) / entythick(i), calculate the thickness reduction rate for each pass, and organize the data of the upper roll radius and lower roll radius of the work roll as shown in the following table:

[0170]

[0171] Step 1: Calculate the forward slip intermediate variable factor.

[0172] xh_kapa(1) = sqrt(((gr(WRU) + gr(WRL)) / 2.0) / entythick(1))

[0173] = sqrt(((565.405 + 565.42) / 2.0) / 200) = 1.68139

[0174] xh_kapa(2) = sqrt(((gr(WRU) + gr(WRL)) / 2.0) / entythick(2))

[0175] = sqrt(((565.405 + 565.42) / 2.0) / 157.400) = 1.89531

[0176] xh_kapa(3) = sqrt(((gr(WRU) + gr(WRL)) / 2.0) / entythick(3))

[0177] = sqrt(((565.405 + 565.42) / 2.0) / 108.192) = 2.28605

[0178] xh_kapa(4) = sqrt(((gr(WRU) + gr(WRL)) / 2.0) / entythick(4))

[0179] = sqrt(((565.405 + 565.42) / 2.0) / 79.892) = 2.66031

[0180] xh_kapa(5) = sqrt(((gr(WRU) + gr(WRL)) / 2.0) / entythick(5))

[0181] = sqrt(((565.405 + 565.42) / 2.0) / 53.021) = 3.26555

[0182] Step 2: Calculate the forward slip factor related to thickness.

[0183] xth_kapa(1) = ((((0.00000471 × xh_kapa(1) - 0.00025518) × xh_kapa(1) + 0.0053778) × xh_kapa(1) - 0.056242) × xh_kapa(1) + 0.31057) × xh_kapa(1) + 0.21879 = ((((0.00000471 × 1.68139 - 0.00025518) × 1.68139 + 0.0053778) × 1.68139 - 0.056242) × 1.68139 + 0.31057) × 1.68139 + 0.21879 = 0.60557

[0184] xth_kapa(2) = ((((0.00000471 * xh_kapa(1) - 0.00025518) * xh_kapa(2) + 0.0053778) * xh_kapa(2) - 0.056242) * xh_kapa(2) + 0.31057) * xh_kapa(2) + 0.21879 = ((((0.00000471 * 1.89531 - 0.00025518) * 1.89531 + 0.0053778) * 1.89531 - 0.056242) * 1.89531 + 0.31057) * 1.89531 + 0.21879 = 0.63882

[0185] xth_kapa(3) = ((((0.00000471 * xh_kapa(3) - 0.00025518) * xh_kapa(3) + 0.0053778) * xh_kapa(3) - 0.056242) * xh_kapa(3) + 0.31057) * xh_kapa(3) + 0.21879 = ((((0.00000471 * 2.28605 - 0.00025518) * 2.28605 + 0.0053778) * 2.28605 - 0.056242) * 2.28605 + 0.31057) * 2.28605 + 0.21879 = 0.69242

[0186] xth_kapa(4) = ((((0.00000471 * xh_kapa(4) - 0.00025518) * xh_kapa(4) + 0.0053778) * xh_kapa(4) - 0.056242) * xh_kapa(4) + 0.31057) * xh_kapa(4) + 0.21879 = ((((0.00000471 * 2.66031 - 0.00025518) * 2.66031 + 0.0053778) * 2.66031 - 0.056242) * 2.66031 + 0.31057) * 2.66031 + 0.21879 = 0.73606

[0187] xth_kapa(5) = ((((0.00000471 * xh_kapa(5) - 0.00025518) * xh_kapa(5) + 0.0053778) * xh_kapa(5) - 0.056242) * xh_kapa(1) + 0.31057) * xh_kapa(5) + 0.21879 = ((((0.00000471 * 3.26555 - 0.00025518) * 3.26555 + 0.0053778) * 3.26555 - 0.056242) * 3.26555 + 0.31057) * 3.26555 + 0.21879 = 0.79322

[0188] Step 3: Calculate the front slip factor related to the reduction ratio.

[0189] xeps_kapa(1) = ((((7.6896 * eps(1) - 10.841) * eps(1) + 4.9006) * eps(1) - 0.8848) * eps(1) + 0.3318) * eps(1) + 0.0 = ((((7.6896 * 21.3% - 10.841) * 21.3% + 4.9006) * 21.3% - 0.8848) * 21.3% + 0.3318) * 21.3% + 0.0 = 0.05895

[0190] xeps_kapa(2) = ((((7.6896 * eps(2) - 10.841) * eps(2) + 4.9006) * eps(2) - 0.8848) * eps(2) + 0.3318) * eps(2) + 0.0 = ((((7.6896 * 31.3% - 10.841) * 31.3% + 4.9006) * 31.3% - 0.8848) * 31.3% + 0.3318) * 31.3% = 0.086399

[0191] xeps_kapa(3) = ((((7.6896 * eps(3) - 10.841) * eps(3) + 4.9006) * eps(3) - 0.8848) * eps(3) + 0.3318) * eps(3) + 0.0 = ((((7.6896 * 26.2% - 10.841) * 26.2% + 4.9006) * 26.2% - 0.8848) * 26.2% + 0.3318) * 26.2% + 0.0 = 0.07262

[0192] xeps_kapa(4) = ((((7.6896 × eps(4) - 10.841) × eps(4) + 4.9006) × eps(4) - 0.8848) × eps(4) + 0.3318) × eps(4) + 0.0 = ((((7.6896 × 33.6% - 10.841) × 33.6% + 4.9006) × 33.6% - 0.8848) × 33.6% + 0.3318) × 33.6% + 0.0 = 0.09233

[0193] xeps_kapa(5) = ((((7.6896 × eps(5) - 10.841) × eps(5) + 4.9006) × eps(5) - 0.8848) × eps(5) + 0.3318) × eps(5) + 0.0 = ((((7.6896 × 34.0% - 10.841) × 34.0% + 4.9006) × 34.0% - 0.8848) × 34.0% + 0.3318) × 34.0% + 0.0 = 0.09318

[0194] Step 4: Calculate the forward slip value.

[0195] forwardslip(1) = xth_kapa(1) × xeps_kapa(1) + 1 = 0.605565 × 0.058945 + 1 = 1.035695

[0196] forwardslip(2) = xth_kapa(2) × xeps_kapa(2) + 1 = 0.63882 × 0.086399 + 1 = 1.055193

[0197] forwardslip(3) = xth_kapa(3) × xeps_kapa(3) + 1 = 0.69242 × 0.072623 + 1 = 1.050285

[0198] forwardslip(4) = xth_kapa(4) × xeps_kapa(4) + 1 = 0.736061 × 0.092327 + 1 = 1.067958

[0199] forwardslip(5) = xth_kapa(5) × xeps_kapa(5) + 1 = 0.793221 × 0.093182 + 1 = 1.073914

[0200] The thickness, rolling speed and forward slip value of each rough rolling pass are as follows in the table:

[0201]

[0202] 3) According to the formulas vexit(i) = v(i) × forwardslip(i) and venty(i) = vexit(i) × exitthick(i) / entythick(i), the exit speeds and entry speeds of each pass are calculated as shown in the following table:

[0203]

[0204] 4) The width of this billet is 1235 mm, the target width of the finished strip is 1260 mm, the cold value of the width at the roughing exit is 1263 mm, and the hot value of the width at the roughing exit is 1289 mm. After calculation, the side reduction amounts of each odd pass are successively: 5.0 mm, 6.0453 mm, 18.315 mm.

[0205] The roll speed correction coefficients coff of the first and third passes of the vertical rolls are both 0.0. According to the formula ve(i) = venty(i) × (1 - coff), the roll speeds of the first and third passes of the vertical rolls are:

[0206] ve(1) = venty(1) × (1 - coff) = 2.200749 × (1 - 0.0) = 2.200749;

[0207] ve(3) = venty(3) × (1 - coff) = 2.8695698 × (1 - 0.0) = 2.8695698;

[0208] Then calculate the roll speeds of other passes of the vertical rolls, and summarize the table as follows:

[0209]

[0210] The roughing mill is rolled with the above control parameters, there is no phenomenon of tail turning up, and the rolling state is good, as specifically Figure 5 shown.

[0211] Example 2:

[0212] This example rolls 430 stainless steel, coil number: 925603802. The billet thickness is 200 mm, and the roughing target thickness is 35 mm; the billet width is 1241 mm, and the target width of the finished strip is 1260 mm.

[0213] 1. Calculation of the roughing flat roll reduction

[0214] The steps for calculating the reduction are as follows:

[0215] 1) The reduction methods of the first and third passes of the flat rolls adopt the RAA method, and the other passes adopt the RA method. The initial reduction amounts of each pass are:

[0216]

[0217] 2) Calculate the total reduction given in rough rolling:

[0218] Since the first pass and the third pass adopt the method of fixed reduction, when calculating the proportional change of reduction to reach the target thickness, it is only executed for the passes other than the first and third passes.

[0219] The total reduction of other passes, that is, the total reduction given in the RA mode, is

[0220] RA1_sum = RA(2) + RA(4) + RA(5) = 45.6 + 24.9 + 16.7 = 87.2 (mm)

[0221] 3) Calculate the reduction ratio of each pass for the passes other than the first and third passes, that is, the ratio of the initial reduction given for each pass in the RA mode to the total reduction given in the RA mode. The reduction ratio of each pass RR(i) is:

[0222] RR(i) = RA(i) / RA1_sum

[0223] The specific values obtained are:

[0224]

[0225] 4) Calculate the actual total reduction in rough rolling:

[0226] RA_sum_act = slthc - barthc = 200 - 35 = 165 (mm)

[0227] 5) Calculate the actual reduction of each pass. The method is:

[0228] Since the first and third passes adopt the fixed reduction control method, that is, the RAA mode, therefore, the initial reduction of the first and third passes is the final actual reduction, that is

[0229] RA_act(1) = RAA(1) = 42.6 mm

[0230] RA_act(3) = RAA(3) = 28.3 mm

[0231] Then calculate the actual total reduction for the passes other than the first and third passes, that is, the actual total reduction in the RA mode. It is obtained that:

[0232] RA1_sum_act = RA_sum_act – RAA(1) - RAA(3) = 165 - 42.6 - 28.3 = 94.1 (mm)

[0233] Calculate the actual reduction of each pass in the RA mode:

[0234] RA_act(2) = RA1_sum_act × RR(2) = 94.1 × 52.29% = 49.208 (mm)

[0235] RA_act(4) = RA1_sum_act × RR(4) = 94.1 × 28.56% = 26.870 (mm)

[0236] RA_act(5) = RA1_sum_act × RR(5) = 94.1 × 19.15% = 18.021 (mm)

[0237] The actual reduction per pass, the actual entrance thickness per pass, and the exit thickness are shown in the following table.

[0238]

[0239] 2. Calculation of vertical roll speed

[0240] 1) The rolling speeds of the horizontal rolls for each pass are as follows:

[0241]

[0242] 2) Calculation of the forward slip values for each pass of the roughing horizontal rolls:

[0243] Based on the entrance thickness and exit thickness of each pass calculated above, and then according to the formula eps(i) = (entythick(i) - exitthick(i)) / entythick(i), calculate the thickness reduction rate for each pass, and organize the data of the upper roll radius and lower roll radius of the working roll as shown in the following table:

[0244]

[0245] Step 1: Calculate the intermediate variable factor of forward slip.

[0246] xh_kapa(1) = sqrt(((gr(WRU) + gr(WRL)) / 2.0) / entythick(1))

[0247] = sqrt(((565.405 + 565.42) / 2.0) / 200) = 1.68139

[0248] xh_kapa(2) = sqrt(((gr(WRU) + gr(WRL)) / 2.0) / entythick(2))

[0249] = sqrt(((565.405 + 565.42) / 2.0) / 157.400) = 1.89531

[0250] xh_kapa(3) = sqrt(((gr(WRU) + gr(WRL)) / 2.0) / entythick(3))

[0251] = sqrt(((565.405 + 565.42) / 2.0) / 108.192) = 2.28605

[0252] xh_kapa(4) = sqrt(((gr(WRU) + gr(WRL)) / 2.0) / entythick(4))

[0253] = sqrt(((565.405 + 565.42) / 2.0) / 79.892) = 2.66031

[0254] xh_kapa(5) = sqrt(((gr(WRU) + gr(WRL)) / 2.0) / entythick(5))

[0255] = sqrt(((565.405 + 565.42) / 2.0) / 53.021) = 3.26555

[0256] Step 2: Calculate the front slip factor related to thickness.

[0257] xth_kapa(1) = ((((0.00000471 × xh_kapa(1) - 0.00025518) × xh_kapa(1) + 0.0053778) × xh_kapa(1) - 0.056242) × xh_kapa(1) + 0.31057) × xh_kapa(1) + 0.21879 = ((((0.00000471 × 1.68139 - 0.00025518) × 1.68139 + 0.0053778) × 1.68139 - 0.056242) × 1.68139 + 0.31057) × 1.68139 + 0.21879 = 0.60557

[0258] xth_kapa(2) = ((((0.00000471 * xh_kapa(1) - 0.00025518) * xh_kapa(2) + 0.0053778) * xh_kapa(2) - 0.056242) * xh_kapa(2) + 0.31057) * xh_kapa(2) + 0.21879 = ((((0.00000471 * 1.89531 - 0.00025518) * 1.89531 + 0.0053778) * 1.89531 - 0.056242) * 1.89531 + 0.31057) * 1.89531 + 0.21879 = 0.63882

[0259] xth_kapa(3) = ((((0.00000471 * xh_kapa(3) - 0.00025518) * xh_kapa(3) + 0.0053778) * xh_kapa(3) - 0.056242) * xh_kapa(3) + 0.31057) * xh_kapa(3) + 0.21879 = ((((0.00000471 * 2.28605 - 0.00025518) * 2.28605 + 0.0053778) * 2.28605 - 0.056242) * 2.28605 + 0.31057) * 2.28605 + 0.21879 = 0.69242

[0260] xth_kapa(4) = ((((0.00000471 * xh_kapa(4) - 0.00025518) * xh_kapa(4) + 0.0053778) * xh_kapa(4) - 0.056242) * xh_kapa(4) + 0.31057) * xh_kapa(4) + 0.21879 = ((((0.00000471 * 2.66031 - 0.00025518) * 2.66031 + 0.0053778) * 2.66031 - 0.056242) * 2.66031 + 0.31057) * 2.66031 + 0.21879 = 0.73606

[0261] xth_kapa(5) = ((((0.00000471 × xh_kapa(5) - 0.00025518) × xh_kapa(5) + 0.0053778) × xh_kapa(5) - 0.056242) × xh_kapa(5) + 0.31057) × xh_kapa(5) + 0.21879 = ((((0.00000471 × 3.26555 - 0.00025518) × 3.26555 + 0.0053778) × 3.26555 - 0.056242) × 3.26555 + 0.31057) × 3.26555 + 0.21879 = 0.79322

[0262] Step 3: Calculate the forward slip factor related to the reduction ratio.

[0263] xeps_kapa(1) = ((((7.6896 × eps(1) - 10.841) × eps(1) + 4.9006) × eps(1) - 0.8848) × eps(1) + 0.3318) × eps(1) + 0.0 = ((((7.6896 × 21.3% - 10.841) × 21.3% + 4.9006) × 21.3% - 0.8848) × 21.3% + 0.3318) × 21.3% + 0.0 = 0.05895

[0264] xeps_kapa(2) = ((((7.6896 × eps(2) - 10.841) × eps(2) + 4.9006) × eps(2) - 0.8848) × eps(2) + 0.3318) × eps(2) + 0.0 = ((((7.6896 × 31.3% - 10.841) × 31.3% + 4.9006) × 31.3% - 0.8848) × 31.3% + 0.3318) × 31.3% = 0.086399

[0265] xeps_kapa(3) = ((((7.6896 × eps(3) - 10.841) × eps(3) + 4.9006) × eps(3) - 0.8848) × eps(3) + 0.3318) × eps(3) + 0.0 = ((((7.6896 × 26.2% - 10.841) × 26.2% + 4.9006) × 26.2% - 0.8848) × 26.2% + 0.3318) × 26.2% + 0.0 = 0.07262

[0266] xeps_kapa(4) = ((((7.6896 * eps(4) - 10.841) * eps(4) + 4.9006) * eps(4) - 0.8848) * eps(4) + 0.3318) * eps(4) + 0.0 = ((((7.6896 * 33.6% - 10.841) * 33.6% + 4.9006) * 33.6% - 0.8848) * 33.6% + 0.3318) * 33.6% + 0.0 = 0.09233

[0267] xeps_kapa(5) = ((((7.6896 * eps(5) - 10.841) * eps(5) + 4.9006) * eps(5) - 0.8848) * eps(5) + 0.3318) * eps(5) + 0.0 = ((((7.6896 * 34.0% - 10.841) * 34.0% + 4.9006) * 34.0% - 0.8848) * 34.0% + 0.3318) * 34.0% + 0.0 = 0.09318

[0268] Step 4: Calculate the forward slip value.

[0269] forwardslip(1) = xth_kapa(1) * xeps_kapa(1) + 1 = 0.605565 * 0.058945 + 1 = 1.035695

[0270] forwardslip(2) = xth_kapa(2) * xeps_kapa(2) + 1 = 0.63882 * 0.086399 + 1 = 1.055193

[0271] forwardslip(3) = xth_kapa(3) * xeps_kapa(3) + 1 = 0.69242 * 0.072623 + 1 = 1.050285

[0272] forwardslip(4) = xth_kapa(4) * xeps_kapa(4) + 1 = 0.736061 * 0.092327 + 1 = 1.067958

[0273] forwardslip(5) = xth_kapa(5) * xeps_kapa(5) + 1 = 0.793221 * 0.093182 + 1 = 1.073914

[0274] The thickness, rolling speed and forward slip value of each rough rolling pass are as follows in the table:

[0275]

[0276] 3) According to the formula vexit(i) = v(i) × forwardslip(i) and the formula venty(i) = vexit(i) × exitthick(i) / entythick(i), the exit speed and entry speed of each pass are calculated as shown in the following table:

[0277]

[0278] 4) The width of the slab is 1241 mm, the target width of the finished strip is 1260 mm, the cold value of the width at the roughing exit is 1265 mm, and the hot value of the width at the roughing exit is 1291 mm. After calculation, the side reduction amounts of each odd pass are as follows: 11.35 mm, 21.826 mm, 20.939 mm.

[0279] The vertical roll speed correction coefficients coff for the 1st and 3rd passes are 0.01 and 0.02 respectively. The vertical roll speeds for the 1st and 3rd passes are:

[0280] ve(1) = venty(1) × (1 - coff) = 2.201 × (1 - 0.01) = 2.179;

[0281] ve(3) = venty(3) × (1 - coff) = 2.870 × (1 - 0.02) = 2.812;

[0282] Then calculate the vertical roll speeds of other passes, and summarize the table as follows:

[0283]

[0284] The roughing mill is rolled with the above control parameters, there is no phenomenon of tail turning up, and the rolling state is good.

[0285] Example 3:

[0286] This example rolls 430 stainless steel, coil number: 925663201. The billet thickness is 180 mm, and the roughing target thickness is 35 mm; the billet width is 1093 mm, and the target width of the finished strip is 1110 mm.

[0287] 1. Calculation of roughing flat roll reduction

[0288] The steps for calculating the reduction are as follows:

[0289] 1) The RAA method is adopted for the reduction of the flat roll in the first and third passes, and the RA method is adopted for other passes. The initial reduction of each pass is:

[0290]

[0291] 2) Calculate the total given reduction in roughing:

[0292] Since the first pass and the third pass adopt the method of fixed reduction, when calculating the equal-proportion change of the reduction to reach the target thickness, it is only executed for the passes other than the first and third passes.

[0293] The total reduction of the other passes, that is, the given total reduction in the RA method, is

[0294] RA1_sum = RA2 + RA4 + RA5 = 45.6 + 24.9 + 16.7 = 94.1 (mm)

[0295] 3) Calculate the proportion of reduction of each pass for the passes other than the first and third passes, that is, the proportion of the given initial reduction of each pass in the RA method to the given total reduction in the RA method. The proportion of reduction of each pass RR(i) is:

[0296] RR(i) = RA(i) / RA1_sum

[0297] The specific values obtained are:

[0298]

[0299] 5) Calculate the actual total reduction of rough rolling:

[0300] RA_sum_act = slthc - barthc = 180 - 35 = 145 (mm)

[0301] 6) Calculate the actual reduction of each pass. The method is:

[0302] Since the first and third passes adopt the fixed reduction control method, that is, the RAA method, therefore, the initial reduction of the first and third passes is the final actual reduction, that is

[0303] RA_act(1) = RAA(1) = 41.2 mm

[0304] RA_act(3) = RAA(3) = 26.1 mm

[0305] Then calculate the actual total reduction of the passes other than the first and third passes, that is, the actual total reduction in the RA method. It is obtained that:

[0306] RA1_sum_act = RA_sum_act – RAA(1) - RAA(3) = 145 - 41.2 - 26.1 = 77.7 (mm)

[0307] Calculate the actual reduction of each pass in the RA method:

[0308] RA_act(2) = RA1_sum_act × RR(2) = 77.7 × 52.29% = 40.632 (mm)

[0309] RA_act(4) = RA1_sum_act × RR(4) = 77.7 × 28.56% = 22.187 (mm)

[0310] RA_act(5) = RA1_sum_act × RR(5) = 77.7 × 19.15% = 14.881 (mm)

[0311] The actual reduction per pass, the actual entry thickness and exit thickness per pass are shown in the following table.

[0312]

[0313] 2. Calculation of vertical roll speed

[0314] 1) The rolling speeds of the horizontal rolls for each pass are as follows:

[0315]

[0316] 2) Calculation of the forward slip values for each pass of the roughing horizontal rolls

[0317] Based on the entry thickness and exit thickness of each pass calculated above, and then according to the formula eps(i) = (entythick(i) - exitthick(i)) / entythick(i), calculate the thickness reduction rate for each pass, and organize the data of the upper roll radius and lower roll radius of the work roll as shown in the following table:

[0318]

[0319] Step 1: Calculate the intermediate variable factor of forward slip.

[0320] xh_kapa(1) = sqrt(((gr(WRU) + gr(WRL)) / 2.0) / entythick(1))

[0321] = sqrt(((559.401 + 559.416) / 2.0) / 180) = 1.7629

[0322] xh_kapa(2) = sqrt(((gr(WRU) + gr(WRL)) / 2.0) / entythick(2))

[0323] = sqrt(((559.401 + 559.416) / 2.0) / 138.8) = 2.007566

[0324] xh_kapa(3) = sqrt(((gr(WRU) + gr(WRL)) / 2.0) / entythick(3))

[0325] = sqrt(((559.401 + 559.416) / 2.0) / 98.168) = 2.38715

[0326] xh_kapa(4) = sqrt(((gr(WRU) + gr(WRL)) / 2.0) / entythick(4))

[0327] = sqrt(((559.401 + 559.416) / 2.0) / 72.068) = 2.78608

[0328] xh_kapa(5) = sqrt(((gr(WRU) + gr(WRL)) / 2.0) / entythick(5))

[0329] = sqrt(((559.401 + 559.416) / 2.0) / 49.881) = 3.34887

[0330] Step 2: Calculate the forward slip factor related to thickness.

[0331] xth_kapa(1) = ((((0.00000471 × xh_kapa(1) - 0.00025518) × xh_kapa(1) + 0.0053778) × xh_kapa(1) - 0.056242) × xh_kapa(1) + 0.31057) × xh_kapa(1) + 0.21879 = ((((0.00000471 × 1.7629 - 0.00025518) × 1.7629 + 0.0053778) × 1.7629 - 0.056242) × 1.7629 + 0.31057) × 1.7629 + 0.21879 = 0.61858

[0332] xth_kapa(2) = ((((0.00000471 × xh_kapa(1) - 0.00025518) × xh_kapa(2) + 0.0053778) × xh_kapa(2) - 0.056242) × xh_kapa(2) + 0.31057) × xh_kapa(2) + 0.21879 = ((((0.00000471 × 2.007566 - 0.00025518) × 2.007566 + 0.0053778) × 2.007566 - 0.056242) × 2.007566 + 0.31057) × 2.007566 + 0.21879 = 0.655128

[0333] xth_kapa(3) = ((((0.00000471 * xh_kapa(3) - 0.00025518) * xh_kapa(3) + 0.0053778) * xh_kapa(3) - 0.056242) * xh_kapa(3) + 0.31057) * xh_kapa(3) + 0.21879 = ((((0.00000471 * 2.38715 - 0.00025518) * 2.38715 + 0.0053778) * 2.38715 - 0.056242) * 2.38715 + 0.31057) * 2.38715 + 0.21879 = 0.70491

[0334] xth_kapa(4) = ((((0.00000471 * xh_kapa(4) - 0.00025518) * xh_kapa(4) + 0.0053778) * xh_kapa(4) - 0.056242) * xh_kapa(4) + 0.31057) * xh_kapa(4) + 0.21879 = ((((0.00000471 * 2.78608 - 0.00025518) * 2.78608 + 0.0053778) * 2.78608 - 0.056242) * 2.78608 + 0.31057) * 2.78608 + 0.21879 = 0.74922

[0335] xth_kapa(5) = ((((0.00000471 * xh_kapa(5) - 0.00025518) * xh_kapa(5) + 0.0053778) * xh_kapa(5) - 0.056242) * xh_kapa(1) + 0.21879 = ((((0.00000471 * 3.34887 - 0.00025518) * 3.34887 + 0.0053778) * 3.34887 - 0.056242) * 3.34887 + 0.31057) * 3.34887 + 0.21879 = 0.79996

[0336] Step 3: Calculate the forward slip factor related to the reduction ratio.

[0337] xeps_kapa(1) = ((((7.6896 × eps(1) - 10.841) × eps(1) + 4.9006) × eps(1) - 0.8848) × eps(1) + 0.3318) × eps(1) + 0.0 = ((((7.6896 × 22.9% - 10.841) × 22.9% + 4.9006) × 22.9% - 0.8848) × 22.9% + 0.3318) × 22.9% + 0.0 = 0.06343

[0338] xeps_kapa(2) = ((((7.6896 × eps(2) - 10.841) × eps(2) + 4.9006) × eps(2) - 0.8848) × eps(2) + 0.3318) × eps(2) + 0.0 = ((((7.6896 × 29.3% - 10.841) × 29.3% + 4.9006) × 29.3% - 0.8848) × 29.3% + 0.3318) × 29.3% = 0.081163

[0339] xeps_kapa(3) = ((((7.6896 × eps(3) - 10.841) × eps(3) + 4.9006) × eps(3) - 0.8848) × eps(3) + 0.3318) × eps(3) + 0.0 = ((((7.6896 × 26.6% - 10.841) × 26.6% + 4.9006) × 26.6% - 0.8848) × 26.6% + 0.3318) × 26.6% + 0.0 = 0.07382

[0340] xeps_kapa(4) = ((((7.6896 × eps(4) - 10.841) × eps(4) + 4.9006) × eps(4) - 0.8848) × eps(4) + 0.3318) × eps(4) + 0.0 = ((((7.6896 × 30.8% - 10.841) × 30.8% + 4.9006) × 30.8% - 0.8848) × 30.8% + 0.3318) × 30.8% + 0.0 = 0.08516

[0341] xeps_kapa(5) = ((((7.6896 × eps(5) - 10.841) × eps(5) + 4.9006) × eps(5) - 0.8848) × eps(5) + 0.3318) × eps(5) + 0.0 = ((((7.6896 × 29.8% - 10.841) × 29.8% + 4.9006) × 29.8% - 0.8848) × 29.8% + 0.3318) × 29.8% + 0.0 = 0.08265

[0342] Step 4: Calculate the forward slip value.

[0343] forwardslip(1) = xth_kapa(1) × xeps_kapa(1) + 1 = 0.61858 × 0.06343 + 1 = 1.039238

[0344] forwardslip(2) = xth_kapa(2) × xeps_kapa(2) + 1 = 0.655128 × 0.081163 + 1 = 1.0531721

[0345] forwardslip(3) = xth_kapa(3) × xeps_kapa(3) + 1 = 0.70491 × 0.07382 + 1 = 1.0520352

[0346] forwardslip(4) = xth_kapa(4) × xeps_kapa(4) + 1 = 0.74922 × 0.08516 + 1 = 1.063806

[0347] forwardslip(5) = xth_kapa(5) × xeps_kapa(5) + 1 = 0.79996 × 0.08265 + 1 = 1.06612

[0348] The thickness, rolling speed and forward slip value of each rough rolling pass are as follows:

[0349]

[0350] 3) According to the formula vexit(i) = v(i) × forwardslip(i) and the formula venty(i) = vexit(i) × exitthick(i) / entythick(i), calculate the exit speed and entry speed of each pass as follows:

[0351]

[0352] 4) The width of this billet is 1093 mm, the target width of the finished strip is 1110 mm, the cold value of the rough rolling exit width is 1113 mm, and the hot value of the rough rolling exit width is 1135 mm. Calculate the side reduction of each odd pass as follows: 9.55 mm, 31.815 mm, 30.915 mm.

[0353] The vertical roll speed correction coefficients coff for the 1st and 3rd passes are 0.00 and 0.03 respectively. The vertical roll speeds for the 1st and 3rd passes are:

[0354] ve(1) = venty(1) × (1 - coff) = 2.208 × (1 - 0.00) = 2.208;

[0355] ve(3) = venty(3) × (1 - coff) = 2.874 × (1 - 0.03) = 2.817;

[0356] Then calculate the vertical roll speeds of other passes, and the summary table is as follows:

[0357]

[0358] The rough rolling stand is rolled with the above control parameters, there is no phenomenon of tail turning up, and the rolling state is good.

[0359] Example 4:

[0360] This example rolls 430 stainless steel, coil number: 925716209. The blank thickness is 200 mm, and the rough rolling target thickness is 35 mm; the blank width is 1037 mm, and the target width of the finished strip is 1040 mm.

[0361] 1. Calculation of rough rolling flat roll reduction

[0362] The steps for calculating the reduction are as follows:

[0363] 1) The reduction methods for the first and third passes of the flat roll adopt the RAA method, and the other passes adopt the RA method. The initial reduction for each pass is:

[0364]

[0365] 2) Calculate the total given reduction in rough rolling:

[0366] Since the first and third passes adopt the method of fixed reduction, when calculating the equal-proportion change of the reduction to reach the target thickness, it is only executed for the other passes except the first and third passes.

[0367] The total reduction of the other passes, that is, the total given reduction in the RA method, is

[0368] RA1_sum = RA(2) + RA(4) + RA(5) = 45.6 + 24.9 + 16.7 = 87.2 (mm)

[0369] 3) Calculate the reduction ratio of each pass for the other passes except the first and third passes, that is, the ratio of the given initial reduction of each pass in the RA method to the total given reduction in the RA method. The reduction ratio RR(i) of each pass is:

[0370] RR(i) = RA(i) / RA1_sum

[0371] The specific values are obtained as:

[0372]

[0373] 4) Calculate the actual total reduction in rough rolling:

[0374] RA_sum_act = slthc - barthc = 200 - 35 = 165 (mm)

[0375] 5) Calculate the actual reduction for each pass, the method is:

[0376] Since the fixed reduction control method, i.e., the RAA method, is adopted for the first and third passes, thus, the initial reduction of the first and third passes is the final actual reduction, that is

[0377] RA_act(1) = RAA(1) = 42.6 mm

[0378] RA_act(3) = RAA(3) = 28.3 mm

[0379] Then calculate the actual total reduction except for the first and third passes, that is, the actual total reduction under the RA method. It is obtained that:

[0380] RA1_sum_act = RA_sum_act – RAA(1) - RAA(3) = 165 - 42.6 - 28.3 = 94.1 (mm)

[0381] Calculate the actual reduction for each pass under the RA method:

[0382] RA_act(2) = RA1_sum_act × RR(2) = 94.1 × 52.29% = 49.208 (mm)

[0383] RA_act(4) = RA1_sum_act × RR(4) = 94.1 × 28.56% = 26.870 (mm)

[0384] RA_act(5) = RA1_sum_act × RR(5) = 94.1 × 19.15% = 18.021 (mm)

[0385] The actual reduction for each pass, the actual entry thickness and exit thickness for each pass are shown in the following table.

[0386]

[0387] 2. Calculation of vertical roll speed

[0388] 1) The rolling speeds for each pass of the flat roll are:

[0389]

[0390] 2) Calculation of the forward slip values for each pass of the roughing flat rolls:

[0391] Based on the entrance thickness and exit thickness of each pass calculated above, and then according to the formula eps(i) = (entythick(i) - exitthick(i)) / entythick(i), calculate the thickness reduction rate of each pass, and organize the data of the upper roll radius and lower roll radius of the work roll as follows:

[0392]

[0393] Step 1: Calculate the intermediate variable factor of the forward slip.

[0394] xh_kapa(1) = sqrt(((gr(WRU) + gr(WRL)) / 2.0) / entythick(1))

[0395] = sqrt(((580.23 + 580.45) / 2.0) / 200) = 1.70344

[0396] xh_kapa(2) = sqrt(((gr(WRU) + gr(WRL)) / 2.0) / entythick(2))

[0397] = sqrt(((580.23 + 580.45) / 2.0) / 157.400) = 1.920167

[0398] xh_kapa(3) = sqrt(((gr(WRU) + gr(WRL)) / 2.0) / entythick(3))

[0399] = sqrt(((580.23 + 580.45) / 2.0) / 108.192) = 2.31603

[0400] xh_kapa(4) = sqrt(((gr(WRU) + gr(WRL)) / 2.0) / entythick(4))

[0401] = sqrt(((580.23 + 580.45) / 2.0) / 79.892) = 2.6952

[0402] xh_kapa(5) = sqrt(((gr(WRU) + gr(WRL)) / 2.0) / entythick(5))

[0403] = sqrt(((580.23 + 580.45) / 2.0) / 53.021) = 3.30838

[0404] Step 2: Calculate the thickness-related forward slip factor.

[0405] xth_kapa(1) = ((((0.00000471 × xh_kapa(1) - 0.00025518) × xh_kapa(1) + 0.0053778) × xh_kapa(1) - 0.056242) × xh_kapa(1) + 0.31057) × xh_kapa(1) + 0.21879 = ((((0.00000471 × 1.70344 - 0.00025518) × 1.70344 + 0.0053778) × 1.70344 - 0.056242) × 1.70344 + 0.31057) × 1.70344 + 0.21879 = 0.60913

[0406] xth_kapa(2) = ((((0.00000471 × xh_kapa(1) - 0.00025518) × xh_kapa(2) + 0.0053778) × xh_kapa(2) - 0.056242) × xh_kapa(2) + 0.31057) × xh_kapa(2) + 0.21879 = ((((0.00000471 × 1.920167 - 0.00025518) × 1.920167 + 0.0053778) × 1.920167 - 0.056242) × 1.920167 + 0.31057) × 1.920167 + 0.21879 = 0.642497

[0407] xth_kapa(3) = ((((0.00000471 × xh_kapa(3) - 0.00025518) × xh_kapa(3) + 0.0053778) × xh_kapa(3) - 0.056242) × xh_kapa(3) + 0.31057) × xh_kapa(3) + 0.21879 = ((((0.00000471 × 2.31603 - 0.00025518) × 2.31603 + 0.0053778) × 2.31603 - 0.056242) × 2.31603 + 0.31057) × 2.31603 + 0.21879 = 0.69618

[0408] xth_kapa(4) = ((((0.00000471 * xh_kapa(4) - 0.00025518) * xh_kapa(4) + 0.0053778) * xh_kapa(4) - 0.056242) * xh_kapa(4) + 0.31057) * xh_kapa(4) + 0.21879 = ((((0.00000471 * 2.6952 - 0.00025518) * 2.6952 + 0.0053778) * 2.6952 - 0.056242) * 2.6952 + 0.31057) * 2.6952 + 0.21879 = 0.73978

[0409] xth_kapa(5) = ((((0.00000471 * xh_kapa(5) - 0.00025518) * xh_kapa(5) + 0.0053778) * xh_kapa(5) - 0.056242) * xh_kapa(5) + 0.31057) * xh_kapa(5) + 0.21879 = ((((0.00000471 * 3.30838 - 0.00025518) * 3.30838 + 0.0053778) * 3.30838 - 0.056242) * 3.30838 + 0.31057) * 3.30838 + 0.21879 = 0.79672

[0410] Step 3: Calculate the front slip factor related to the reduction ratio.

[0411] xeps_kapa(1) = ((((7.6896 * eps(1) - 10.841) * eps(1) + 4.9006) * eps(1) - 0.8848) * eps(1) + 0.3318) * eps(1) + 0.0 = ((((7.6896 * 21.3% - 10.841) * 21.3% + 4.9006) * 21.3% - 0.8848) * 21.3% + 0.3318) * 21.3% + 0.0 = 0.05895

[0412] xeps_kapa(2) = ((((7.6896 * eps(2) - 10.841) * eps(2) + 4.9006) * eps(2) - 0.8848) * eps(2) + 0.3318) * eps(2) + 0.0 = ((((7.6896 * 31.3% - 10.841) * 31.3% + 4.9006) * 31.3% - 0.8848) * 31.3% + 0.3318) * 31.3% = 0.086399

[0413] xeps_kapa(3) = ((((7.6896 * eps(3) - 10.841) * eps(3) + 4.9006) * eps(3) - 0.8848) * eps(3) + 0.3318) * eps(3) + 0.0 = ((((7.6896 * 26.2% - 10.841) * 26.2% + 4.9006) * 26.2% - 0.8848) * 26.2% + 0.3318) * 26.2% + 0.0 = 0.07262

[0414] xeps_kapa(4) = ((((7.6896 * eps(4) - 10.841) * eps(4) + 4.9006) * eps(4) - 0.8848) * eps(4) + 0.3318) * eps(4) + 0.0 = ((((7.6896 * 33.6% - 10.841) * 33.6% + 4.9006) * 33.6% - 0.8848) * 33.6% + 0.3318) * 33.6% + 0.0 = 0.09233

[0415] xeps_kapa(5) = ((((7.6896 * eps(5) - 10.841) * eps(5) + 4.9006) * eps(5) - 0.8848) * eps(5) + 0.3318) * eps(5) + 0.0 = ((((7.6896 * 34.0% - 10.841) * 34.0% + 4.9006) * 34.0% - 0.8848) * 34.0% + 0.3318) * 34.0% + 0.0 = 0.09318

[0416] Step 4: Calculate the forward slip value.

[0417] forwardslip(1) = xth_kapa(1) * xeps_kapa(1) + 1 = 0.60913 * 0.05895 + 1 = 1.035905

[0418] forwardslip(2) = xth_kapa(2) * xeps_kapa(2) + 1 = 0.642497 * 0.086399 + 1 = 1.055511

[0419] forwardslip(3) = xth_kapa(3) * xeps_kapa(3) + 1 = 0.69618 * 0.07262 + 1 = 1.050558

[0420] forwardslip(4) = xth_kapa(4) × xeps_kapa(4) + 1 = 0.73978 × 0.09233 + 1 = 1.068302

[0421] forwardslip(5) = xth_kapa(5) × xeps_kapa(5) + 1 = 0.79672 × 0.09318 + 1 = 1.074240

[0422] The thickness, rolling speed and forward slip value of each roughing pass are as follows:

[0423]

[0424] 3) According to the formula vexit(i) = v(i) × forwardslip(i) and the formula venty(i) = vexit(i) × exitthick(i) / entythick(i), the exit speed and entry speed of each pass are calculated as follows:

[0425]

[0426] 4) The width of this billet is 1037 mm, the target width of the finished strip is 1040 mm, the cold value of the roughing exit width is 1043 mm, and the hot value of the roughing exit width is 1063 mm. After calculation, the side reduction amounts of each odd pass are: 40.683 mm, 51.867 mm, 30.155 mm.

[0427] The vertical roll speed correction coefficients coff for the 1st and 3rd passes are 0.04 and 0.05 respectively. The vertical roll speeds for the 1st and 3rd passes are:

[0428] ve(1) = venty(1) × (1 - coff) = 2.201 × (1 - 0.04) = 2.113;

[0429] ve(3) = venty(3) × (1 - coff) = 2.870 × (1 - 0.05) = 2.727;

[0430] Then calculate the vertical roll speeds of other passes, and the summary table is as follows:

[0431]

[0432] The roughing mill is rolled with the above control parameters, without the phenomenon of tail turning up, and the rolling state is good.

[0433] Example 5:

[0434] This example involves rolling 430 stainless steel with a coil number of 925768601. The blank thickness is 200 mm, and the rough rolling target thickness is 35 mm; the blank width is 1288 mm, and the target width of the finished strip is 1290 mm.

[0435] 1. Calculation of flat roll reduction in rough rolling

[0436] The steps for calculating the reduction are as follows:

[0437] 1) For the first and third passes of the flat roll, the RAA method is used for the reduction, and the RA method is used for other passes. The initial reduction for each pass is:

[0438]

[0439] 2) Calculate the total given reduction in rough rolling:

[0440] Since the first and third passes use a fixed reduction method, when calculating the proportional change in reduction to reach the target thickness, it is only executed for other passes except the first and third passes.

[0441] The total reduction for other passes, that is, the given total reduction under the RA method, is

[0442] RA1_sum = RA(2) + RA(4) + RA(5) = 45.6 + 24.9 + 16.7 = 87.2 (mm)

[0443] 3) Calculate the reduction ratio for each pass of other passes except the first and third passes, that is, the ratio of the given initial reduction for each pass under the RA method to the given total reduction under the RA method. The reduction ratio RR(i) for each pass is:

[0444] RR(i) = RA(i) / RA1_sum

[0445] The specific values are obtained as:

[0446]

[0447] 4) Calculate the actual total reduction in rough rolling:

[0448] RA_sum_act = slthc - barthc = 200 - 35 = 165 (mm)

[0449] 5) Calculate the actual reduction for each pass. The method is:

[0450] Since the first and third passes use a fixed reduction control method, that is, the RAA method, therefore, the initial reduction for the first and third passes is the final actual reduction, that is

[0451] RA_act(1) = RAA(1) = 42.6 mm

[0452] RA_act(3) = RAA(3) = 28.3 mm

[0453] Then calculate the actual total reduction except for the first and third passes, that is, the actual total reduction in the RA method. It is obtained that:

[0454] RA1_sum_act = RA_sum_act – RAA(1) - RAA(3) = 165 - 42.6 - 28.3 = 94.1 (mm)

[0455] Calculate the actual reduction per pass in the RA method:

[0456] RA_act(2) = RA1_sum_act × RR(2) = 94.1 × 52.29% = 49.208 (mm)

[0457] RA_act(4) = RA1_sum_act × RR(4) = 94.1 × 28.56% = 26.870 (mm)

[0458] RA_act(5) = RA1_sum_act × RR(5) = 94.1 × 19.15% = 18.021 (mm)

[0459] The actual reduction per pass, the actual entrance thickness per pass, and the exit thickness are shown in the following table.

[0460]

[0461] 2. Calculation of vertical roll speed

[0462] 1) The rolling speeds of the horizontal rolls for each pass are:

[0463]

[0464] 2) Calculation of the forward slip values for each pass of the roughing horizontal rolls:

[0465] According to the entrance thickness and exit thickness of each pass calculated above, and then according to the formula eps(i) = (entythick(i) - exitthick(i)) / entythick(i), calculate the thickness reduction rate of each pass, and organize the data of the upper roll radius and lower roll radius of the work roll, as shown in the following table:

[0466]

[0467] Step 1: Calculate the intermediate variable factor of the forward slip.

[0468] xh_kapa(1) = sqrt(((gr(WRU) + gr(WRL)) / 2.0) / entythick(1))

[0469] = sqrt(((581.31 + 581.52) / 2.0) / 200) = 1.70501

[0470] xh_kapa(2) = sqrt(((gr(WRU) + gr(WRL)) / 2.0) / entythick(2))

[0471] = sqrt(((581.31 + 581.52) / 2.0) / 157.400) = 1.921944

[0472] xh_kapa(3) = sqrt(((gr(WRU) + gr(WRL)) / 2.0) / entythick(3))

[0473] = sqrt(((581.31 + 581.52) / 2.0) / 108.192) = 2.31817

[0474] xh_kapa(4) = sqrt(((gr(WRU) + gr(WRL)) / 2.0) / entythick(4))

[0475] = sqrt(((581.31 + 581.52) / 2.0) / 79.892) = 2.69769

[0476] xh_kapa(5) = sqrt(((gr(WRU) + gr(WRL)) / 2.0) / entythick(5))

[0477] = sqrt(((581.31 + 581.52) / 2.0) / 53.021) = 3.31144

[0478] Step 2: Calculate the thickness-related forward slip factor.

[0479] xth_kapa(1) = ((((0.00000471 * xh_kapa(1) - 0.00025518) * xh_kapa(1) + 0.0053778) * xh_kapa(1) - 0.056242) * xh_kapa(1) + 0.31057) * xh_kapa(1) + 0.21879 = ((((0.00000471 * 1.70501 - 0.00025518) * 1.70501 + 0.0053778) * 1.70501 - 0.056242) * 1.70501 + 0.31057) * 1.70501 + 0.21879 = 0.60938

[0480] xth_kapa(2) = ((((0.00000471 * xh_kapa(1) - 0.00025518) * xh_kapa(2) + 0.0053778) * xh_kapa(2) - 0.056242) * xh_kapa(2) + 0.31057) * xh_kapa(2) + 0.21879 = ((((0.00000471 * 1.921944 - 0.00025518) * 1.921944 + 0.0053778) * 1.921944 - 0.056242) * 1.921944 + 0.31057) * 1.921944 + 0.21879 = 0.642758

[0481] xth_kapa(3) = ((((0.00000471 * xh_kapa(3) - 0.00025518) * xh_kapa(3) + 0.0053778) * xh_kapa(3) - 0.056242) * xh_kapa(3) + 0.31057) * xh_kapa(3) + 0.21879 = ((((0.00000471 * 2.31817 - 0.00025518) * 2.31817 + 0.0053778) * 2.31817 - 0.056242) * 2.31817 + 0.31057) * 2.31817 + 0.21879 = 0.69645

[0482] xth_kapa(4) = ((((0.00000471 * xh_kapa(4) - 0.00025518) * xh_kapa(4) + 0.0053778) * xh_kapa(4) - 0.056242) * xh_kapa(4) + 0.31057) * xh_kapa(4) + 0.21879 = ((((0.00000471 * 2.69769 - 0.00025518) * 2.69769 + 0.0053778) * 2.69769 - 0.056242) * 2.69769 + 0.31057) * 2.69769 + 0.21879 = 0.74005

[0483] xth_kapa(5) = ((((0.00000471 * xh_kapa(5) - 0.00025518) * xh_kapa(5) + 0.0053778) * xh_kapa(5) - 0.056242) * xh_kapa(5) + 0.31057) * xh_kapa(5) + 0.21879 = ((((0.00000471 * 3.31144 - 0.00025518) * 3.31144 + 0.0053778) * 3.31144 - 0.056242) * 3.31144 + 0.31057) * 3.31144 + 0.21879 = 0.79697

[0484] Step 3: Calculate the forward slip factor related to the reduction ratio.

[0485] xeps_kapa(1) = ((((7.6896 * eps(1) - 10.841) * eps(1) + 4.9006) * eps(1) - 0.8848) * eps(1) + 0.3318) * eps(1) + 0.0 = ((((7.6896 * 21.3% - 10.841) * 21.3% + 4.9006) * 21.3% - 0.8848) * 21.3% + 0.3318) * 21.3% + 0.0 = 0.05895

[0486] xeps_kapa(2) = ((((7.6896 * eps(2) - 10.841) * eps(2) + 4.9006) * eps(2) - 0.8848) * eps(2) + 0.3318) * eps(2) + 0.0 = ((((7.6896 * 31.3% - 10.841) * 31.3% + 4.9006) * 31.3% - 0.8848) * 31.3% + 0.3318) * 31.3% = 0.086399

[0487] xeps_kapa(3) = ((((7.6896 * eps(3) - 10.841) * eps(3) + 4.9006) * eps(3) - 0.8848) * eps(3) + 0.3318) * eps(3) + 0.0 = ((((7.6896 * 26.2% - 10.841) * 26.2% + 4.9006) * 26.2% - 0.8848) * 26.2% + 0.3318) * 26.2% + 0.0 = 0.07262

[0488] xeps_kapa(4) = ((((7.6896 * eps(4) - 10.841) * eps(4) + 4.9006) * eps(4) - 0.8848) * eps(4) + 0.3318) * eps(4) + 0.0 = ((((7.6896 * 33.6% - 10.841) * 33.6% + 4.9006) * 33.6% - 0.8848) * 33.6% + 0.3318) * 33.6% + 0.0 = 0.09233

[0489] xeps_kapa(5) = ((((7.6896 * eps(5) - 10.841) * eps(5) + 4.9006) * eps(5) - 0.8848) * eps(5) + 0.3318) * eps(5) + 0.0 = ((((7.6896 * 34.0% - 10.841) * 34.0% + 4.9006) * 34.0% - 0.8848) * 34.0% + 0.3318) * 34.0% + 0.0 = 0.09318

[0490] Step 4: Calculate the forward slip value.

[0491] forwardslip(1) = xth_kapa(1) * xeps_kapa(1) + 1 = 0.60938 * 0.05895 + 1 = 1.035920

[0492] forwardslip(2) = xth_kapa(2) * xeps_kapa(2) + 1 = 0.642758 * 0.086399 + 1 = 1.055533

[0493] forwardslip(3) = xth_kapa(3) * xeps_kapa(3) + 1 = 0.69645 * 0.07262 + 1 = 1.050578

[0494] forwardslip(4) = xth_kapa(4) × xeps_kapa(4) + 1 = 0.74005 × 0.09233 + 1 = 1.068326

[0495] forwardslip(5) = xth_kapa(5) × xeps_kapa(5) + 1 = 0.79697 × 0.09318 + 1 = 1.074263

[0496] The thickness, rolling speed and forward slip value of each roughing pass are as follows:

[0497]

[0498] 3) According to the formula vexit(i) = v(i) × forwardslip(i) and the formula venty(i) = vexit(i) × exitthick(i) / entythick(i), the exit speed and entry speed of each pass are calculated as follows:

[0499]

[0500] 4) The width of this billet is 1288 mm, the target width of the finished strip is 1290 mm, the cold value of the roughing exit width is 1300 mm, and the hot value of the roughing exit width is 1325 mm. After calculation, the side pressure of each odd pass is as follows: 11.154 mm, 60.157 mm, 20.137 mm.

[0501] The roll speed correction coefficients coff of the first and third passes are 0.01 and 0.05 respectively. The roll speeds of the first and third passes are:

[0502] ve(1) = venty(1) × (1 - coff) = 2.201 × (1 - 0.01) = 2.179;

[0503] ve(3) = venty(3) × (1 - coff) = 2.870 × (1 - 0.05) = 2.727;

[0504] Then calculate the roll speeds of other passes, and the summary table is as follows:

[0505]

[0506] The roughing mill is rolled with the above control parameters, without the phenomenon of tail turning up, and the rolling state is good.

[0507] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other substitutions, modifications, combinations, changes, simplifications, etc. made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A control method for solving the scratch at the tail of stainless steel rough rolling, characterized in that, Including controlling the reduction of the horizontal rolls in each rough rolling pass and controlling the speed of the vertical rolls in each rough rolling pass; The controlling the reduction of the horizontal rolls in each rough rolling pass includes: Determining the given initial reduction RA(i) for the i-th pass, where i is an integer from 1 to 5; Calculate the total reduction given in rough rolling Calculating the reduction ratio RR(i) for the i-th pass = RA(i) / RA_sum; Calculating the actual total reduction RA_sum_act of rough rolling = slthc - barthc, where slthc represents the slab thickness and barthc represents the rough rolling target thickness; Calculating the actual reduction RA_act(i) for the i-th pass = RA_sum_act × RR(i); The controlling the speed of the vertical rolls in each rough rolling pass includes: Determining the rolling speed v(i) of the horizontal rolls in the i-th pass; Calculating the exit speed vexit(i) of the horizontal rolls in the i-th pass = v(i) × forwardslip(i), where forwardslip(i) represents the forward slip value of the i-th pass; Calculating the entry speed venty(i) of the i-th pass = vexit(i) × exitthick(i) / entythick(i), where exitthick(i) represents the exit thickness of the i-th pass in mm and entythick(i) represents the entry thickness of the i-th pass in mm; Calculating the speed ve(i) of the i-th vertical roll, where when i is 1, 3 or 5, ve(i) = venty(i), and when i is 2 or 4, ve(i) = vexit(i).

2. The control method for solving the tail scratching problem in stainless steel rough rolling according to claim 1, wherein The stainless steel is stainless steel of grade 430.

3. The control method for solving the tail scratch of stainless steel rough rolling according to claim 2, characterized in that, The thickness of the slab of the stainless steel is 200 mm.

4. The control method for solving the scratch at the tail of stainless steel rough rolling according to claim 3, characterized in that, RA_act(1) = RA(1) = 42.6 mm, RA_act(3) = RA(3) = 28.3 mm.

5. The control method for solving the scratch at the tail of stainless steel rough rolling according to claim 2, wherein, The thickness of the slab of the stainless steel is 180 mm.

6. The control method for solving the scratch at the tail of stainless steel rough rolling according to claim 5, characterized in that, RA_act(1) = RA(1) = 41.2 mm, RA_act(3) = RA(3) = 26.1 mm.

7. The control method for solving the scratch at the tail of stainless steel rough rolling according to claim 4 or 6, characterized in that, The controlling the reduction of the horizontal rolls in each rough rolling pass includes: Determining the given initial reductions RA(2), RA(4) and RA(5) for the 2nd, 4th and 5th passes; Calculating the given total reduction RA1_sum of rough rolling for the 2nd, 4th and 5th passes = RA(2) + RA(4) + RA(5); Calculating the reduction ratio RR(i) for the 2nd, 4th and 5th passes = RA(i) / RA1_sum, where i is 2, 4 or 5; Calculating the actual total reduction RA_sum_act of rough rolling = slthc - barthc, where slthc represents the slab thickness and barthc represents the rough rolling target thickness; Calculating the actual reduction RA_act(i) for the 2nd, 4th and 5th passes = RA1_sum_act × RR(i), where RA1_sum_act = RA_sum_act - RA(1) - RA(3).

8. The control method for solving the scratch at the tail of stainless steel rough rolling according to claim 4 or 6, characterized in that, The controlling the speed of the vertical rolls in each rough rolling pass includes controlling the speed of the vertical rolls in the 1st and 3rd passes, where ve(i) = venty(i) × (1 - coff), where i is 1 or 3 and coff represents the vertical roll speed correction coefficient.

9. The control method for solving the scratch at the tail of stainless steel rough rolling according to claim 8, characterized in that, The value of the vertical roll speed correction coefficient coff is as follows: 。

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