Method for calculating equivalent rolling kilometers of rollers of twenty-high rolling mill

Abstract

The invention relates to a method for calculating equivalent rolling kilometers of rollers of a twenty-high rolling mill, which comprises the following steps of: acquiring equipment parameters and selected target process parameters of the rolling mill, as well as inter-roller pressure and rolling pressure of each roller, and then collecting actual process parameters, the inter-roller pressure and the rolling pressure of each roller, and the current actual rolling kilometers. Then, under actual process parameters, the abrasion and crack depth of each roller is calculated, weighted summation is conducted on fatigue and abrasion distribution curves, then an objective function and an iterative variable initial value are given, weighted summation is conducted on the fatigue and abrasion distribution curves under target process parameters, finally, the two values are compared, and finally, the initial value of the objective function and the initial value of the iterative variable are obtained. According to the method, the rolling kilometers under the actual process parameters are converted into the equivalent rolling kilometers under the target process parameters, and a scientific basis is provided for the whole-cycle health degree analysis theory of the rolling mill and the whole-life-cycle health management technology of the roller.

Description

Technical Field

[0001] The invention belongs to the technical field of cold rolling and relates to a method for calculating the equivalent rolling kilometres of a twenty-high rolling mill roll. Background Art

[0002] The rolling mill is an advanced rolling mill developed to meet the demands of rolling high-precision, ultra-thin metal strip. It evolved from improvements to traditional rolling mills and progressed with advances in cold rolling technology. Early four- and six-high mills often faced challenges such as inaccurate thickness control and poor strip shape when rolling harder or thinner materials. To overcome these challenges, the rolling mill was developed. By increasing the number of rolls, it evenly distributes pressure on the material, effectively reducing roll deformation and improving rolling accuracy and strip shape control.

[0003] Roller mills, due to their complex structure and high precision requirements, are widely used in the production of high-precision plate. During production operations, the health of the rolls, wear and tear costs, and the impact of replacement on production efficiency are directly related to overall production profitability. As a core component of a rolling mill, rolls are susceptible to wear, cracks, or fatigue damage under high loads and long periods of operation, affecting plate rolling quality and production stability. To extend roll life and maintain production accuracy, roll health is typically monitored in real time, and grinding, adjustment, or replacement measures are implemented to prevent excessive wear and failure.

[0004] Roller wear not only incurs replacement costs but also directly increases maintenance expenses, impacting overall production budgets. While rolling mileage provides a visual indicator of roll usage, it cannot fully reflect the actual wear and fatigue level. For example, under heavy loads or high temperatures, roll wear intensifies, and even with a short rolling mileage, roll wear may already be significant. Therefore, simply measuring rolling mileage often fails to accurately reflect the true extent of roll wear. Summary of the Invention

[0005] In order to solve the above problems, the technical solution adopted by the present invention is: a method for calculating the equivalent rolling kilometers of a twenty-high rolling mill roll, comprising the following steps:

[0006] S1: Obtain equipment specifications of the rolling mill and characteristic parameters of the roll surface material;

[0007] S2: Selecting the target process parameter C0 of the rolling mill and calculating the inter-roller pressure and rolling pressure distribution of each roll of the rolling mill corresponding to the target process parameter based on the working parameters of the rolling mill;

[0008] S3: obtaining the actual process parameters C1 of the rolling mill, and calculating the inter-roller pressure and rolling pressure distribution of each roll of the rolling mill corresponding to the actual process parameters and the current actual rolling mileage based on the working parameters of the rolling mill;

[0009] S4: Under the actual process parameters C1 of the rolling mill and when rolling the corresponding mileage L1, a weighted sum F1 of the fatigue crack distribution curve and the wear distribution curve is calculated based on the inter-roller pressure and rolling pressure of each roll corresponding to the actual process parameters and the current actual rolling mileage;

[0010] S5: Set the iteration initial value L;

[0011] S6: Under the target process parameters C0, the iteration step length ΔL, the initial value of the iteration variable k=0, and the rolling kilometers L+k*ΔL, the fatigue crack distribution curve T0(y) and the wear distribution curve W0(y) of the roll are calculated based on the inter-roller pressure and rolling pressure of each roll corresponding to the target process parameters, and then the weighted calculation F0 is performed;

[0012] S7: Determine whether |F1-F0| is less than the threshold value ε. If the determination result is yes, proceed to step S7. If the determination result is no, set k+1 and proceed to step S6.

[0013] S8: Calculate the equivalent rolling kilometers L0 = L + k * ΔL required for the rolling mill to produce equivalent fatigue cracks and wear on the rolls under the target process parameters C0.

[0014] Furthermore, under the actual process parameters C1 of the rolling mill and when rolling the corresponding mileage L1, the calculation process of the weighted sum F1 of the fatigue crack distribution curve and the wear distribution curve based on the inter-roller pressure and rolling pressure distribution of each roll corresponding to the actual process parameters and the current actual rolling mileage is as follows:

[0015] S41: dividing the mill roll wear into inter-roller wear and wear between the roll and the workpiece, dividing the wear of each roll into several sections, calculating the wear amount of each section in sections, then calculating the wear curve of each section based on the inter-roller pressure and the lateral distribution of the rolling pressure, and finally drawing the roll wear distribution curve W1(y);

[0016] S42: Calculate the crack depth of the roll and draw the overall fatigue distribution curve T1(y) of the roll;

[0017] S43: Taking the weighted sum of the fatigue crack distribution curve T1(y) and the wear distribution curve W1(y) of the rolling mill roller.

[0018] Furthermore, the expression for the inter-roller wear between the rollers is as follows:

[0019]

[0020] The expression of wear between the work roll and the workpiece is as follows:

[0021]

[0022] Where y is the transverse coordinate of the roll and strip unit; Q ro (y), Q rp (y) are rolling L t The wear of the roll and the work roll when the length of the strip is less than 100 mm; q(y) is the distribution of the contact pressure between the rolls; D is the roll diameter; R 10 ,R 20 are the working radius of the two contacting rollers; R1(y), R2(y) are the load radius distribution values of the two rollers; R 1c (y) is the original grinding radius distribution value of roller 1; R 2c (y) is the original radius of roller 2; ΔR 1t (y),ΔR 2t (y) are the radial distribution values of the thermal crown of the two rolls; q′(y) is the distribution of rolling pressure; D s is the diameter of the working roll; C(y) is a function related to the lateral flow of metal in the roll gap; h c is the average thickness of the strip deformation zone.

[0023] Furthermore, the crack depth of the roller is calculated by numerically inverting the crack depth of the roller under the current rolling kilometer using the following formula:

[0024]

[0025] Where N is the number of stress cycles; a is the crack depth; E is the elastic modulus of the roller surface material; ε f is the fracture ductility; ΔK is the stress intensity factor range; Δσ is the cyclic stress change amplitude; ΔK th is the roller fatigue threshold; σ 0.2 is the yield limit of the roller surface material; γ is the material determination constant; a0 is the initial crack depth of the roller; a1 is the extension length of the crack generated after the roller has rolled for L kilometers.

[0026] Furthermore, the following formula is used to perform weighted summation of the fatigue crack distribution curve T1(y) and the wear distribution curve W1(y) of the rolling mill.

[0027] F1=0.63∑T1(y)+0.37∑W1(y)

[0028] Furthermore, the working parameters of the rolling mill include the diameter D of the working roll. S , the diameter D of the first intermediate roller P , diameter D of the second intermediate roller JK , diameter D of the support roller CD , the roller length L of the working roller S , the first intermediate roller's roller length L P, the roller length L of the second intermediate roller JK , Roller length L of the support roller CD ; Yield limit of roller surface material σ 0.2 ; Material determination constant γ; Cyclic stress change amplitude Δσ.

[0029] A device for calculating the equivalent rolling kilometers of a twenty-high rolling mill roll, characterized by comprising:

[0030] Acquisition module: used to obtain equipment specifications of the rolling mill and characteristic parameters of the roll surface material;

[0031] Calculation module 1: used to select the target process parameter C0 of the rolling mill and calculate the inter-roll pressure and rolling pressure distribution of each roll of the rolling mill corresponding to the target process parameter based on the working parameters of the rolling mill;

[0032] Calculation module II: used to obtain the actual process parameters C1 of the rolling mill, and calculate the inter-roller pressure and rolling pressure distribution of each roll of the rolling mill corresponding to the actual process parameters and the current actual rolling mileage based on the working parameters of the rolling mill;

[0033] Calculation module III: Under the actual process parameters C1 of the rolling mill and the corresponding rolling mileage L1, the weighted sum F1 of the fatigue crack distribution curve and the wear distribution curve is calculated based on the inter-roller pressure and rolling pressure of each roll corresponding to the actual process parameters and the current actual rolling mileage;

[0034] Calculation module IV: Under the target process parameters C0, set the iteration initial value L, iteration step length ΔL, iteration variable initial value k = 0, and when the rolling kilometers are L + k * ΔL, calculate the fatigue crack distribution curve T0(y) and wear distribution curve W0(y) of the roll based on the inter-roller pressure and rolling pressure of each roll corresponding to the target process parameters, and then calculate F0 by weighting them;

[0035] Judgment module: judge |F1-F0|<threshold ε, if the judgment result is yes, go to step S7, if the judgment result is no, set k+1, go to step calculation module IV;

[0036] Calculation module V: Calculates the equivalent rolling kilometers required for the rolling mill to produce equivalent fatigue cracks and wear under the target process parameters C0.

[0037] A computer device includes: a processor and a memory, wherein the memory stores a program module, and the program module runs on the processor to implement any one of the methods described above.

[0038] The present invention provides a method for calculating the equivalent rolling kilometres of a twenty-high mill roll. Compared with the prior art, the method of the present invention fully considers the influence of the maximum unit rolling load and its lateral distribution (including inter-roller pressure and rolling pressure) on roll wear and fatigue, and establishes a corresponding equivalent rolling kilometres model in combination with the specific rolling plan and actual working conditions.

[0039] The specific operation for calculating the equivalent rolling kilometers is as follows: first, the equipment parameters of the twenty rollers and the target process parameters are collected, as well as the inter-roller pressure and rolling pressure of each roller. Then, the actual process parameters, the inter-roller pressure and rolling pressure of each roller, and the current actual rolling kilometers are collected. Then, under the actual process parameters, the wear and crack depth of each roller are calculated, and the fatigue and wear distribution curves are weighted and summed. Subsequently, the objective function and the initial values of the iterative variables are given, and the fatigue and wear distribution curves are weighted and summed under the target process parameters. Finally, these two values are compared, and the equivalent rolling kilometers of the rollers are output when the judgment conditions are met. The method of the present invention can convert the rolling kilometers under the actual process parameters into the equivalent rolling kilometers under the target process parameters, providing a scientific basis for the full-cycle health analysis theory of the rolling mill and the health management technology of the rollers throughout their life cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0041] Figure 1 A flow chart showing the calculation of equivalent rolling kilometers of a rolling mill roll according to the present invention;

[0042] Figure 2 It is a transverse segmented schematic diagram of the wear of the roller system of the rolling mill in the present invention. DETAILED DESCRIPTION

[0043] It should be noted that, unless there is any conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0044] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0045] Figure 1 A flow chart showing the calculation of equivalent rolling kilometers of a rolling mill roll according to the present invention;

[0046] A method for calculating the equivalent rolling kilometers of a twenty-high rolling mill roll comprises the following steps:

[0047] S1: Obtain equipment specifications of the rolling mill and characteristic parameters of the roll surface material;

[0048] S2: Selecting the target process parameter C0 of the rolling mill and calculating the inter-roller pressure and rolling pressure distribution of each roll of the rolling mill corresponding to the target process parameter based on the working parameters of the rolling mill;

[0049] S3: obtaining the actual process parameters C1 of the rolling mill, and calculating the inter-roller pressure and rolling pressure distribution of each roll of the rolling mill corresponding to the actual process parameters and the current actual rolling mileage based on the working parameters of the rolling mill;

[0050] S4: Under the actual process parameters C1 of the rolling mill and when rolling the corresponding mileage L1, a weighted sum F1 of the fatigue crack distribution curve and the wear distribution curve is calculated based on the inter-roller pressure and rolling pressure of each roll corresponding to the actual process parameters and the current actual rolling mileage;

[0051] S5: Set the initial value L of the iteration,

[0052] S6: Under the target process parameters C0, the iteration step length ΔL, the initial value of the iteration variable k=0, and the rolling kilometers L+k*ΔL, the fatigue crack distribution curve T0(y) and the wear distribution curve W0(y) of the roll are calculated based on the inter-roller pressure and rolling pressure of each roll corresponding to the target process parameters, and then the weighted calculation F0 is performed;

[0053] S7: Determine whether |F1-F0| is less than the threshold ε. If the judgment result is yes, proceed to step S7. If the judgment result is no, set k+1 and proceed to step S6. The threshold ε is 0.1.

[0054] S8: Calculate the equivalent rolling kilometers L0=L+k*ΔL required for the rolling mill to produce equivalent fatigue cracks and wear on the rolls under the target process parameters C0.

[0055] After step S1 is executed, S2 and S3 are executed in parallel, and then S4 / S5 / S6 / S7 / S8 are executed sequentially.

[0056] The working parameters of the rolling mill mainly include: the diameters D of the working roll, the first intermediate roll, the second intermediate roll, and the support roll. S ,D P ,D JK ,D CD , mm; Roller length L of working roll, first intermediate roll, second intermediate roll and backup roll S ,L P ,L JK ,L CD , mm; yield strength of roller surface material σ 0.2 , mpa; material determination constant γ; cyclic stress change amplitude Δσ, mpa;

[0057] The target process parameters C0 mainly include: the front and rear tensions of the strip T0, T1, t; the inlet and outlet thicknesses of the strip h0, h1, mm; the strip width B, mm; the yield strength of the strip K, mPa; the total rolling pressure P, t; the elastic modulus E, gPa; and the Poisson's ratio v. That is, C0 = {T0, T1, h0, h1, B, K, P, E, v}.

[0058] The process parameters C1 mainly include the front and rear tensions of the strip T0, T1, t; the inlet and outlet thicknesses of the strip h0, h1, mm; the strip width B, mm; the yield strength of the strip K, mPa; the total rolling pressure P, t; the elastic modulus E, gPa; the Poisson's ratio v; that is, C1 = {T0, T1, h0, h1, B, K, P, E, v} and the actual rolling kilometer L1, km;

[0059] Figure 2 This is a schematic diagram of the transverse segmentation of the wear of the roller system of the rolling mill in the present invention. Figure 2 , wherein the first part is in contact with the workpiece and an intermediate roll; the second part is in contact with an intermediate roll; and the third part has no contact.

[0060] Furthermore, under the actual process parameters C1 of the rolling mill and when rolling the corresponding mileage L1, the calculation process of the weighted sum F1 of the fatigue crack distribution curve and the wear distribution curve based on the inter-roller pressure and rolling pressure distribution of each roll corresponding to the actual process parameters and the current actual rolling mileage is as follows:

[0061] S41: dividing the mill roll wear into inter-roller wear and wear between the roll and the workpiece, dividing the wear of each roll into several sections, calculating the wear amount of each section in sections, then calculating the wear curve of each section based on the inter-roller pressure and the lateral distribution of the rolling pressure, and finally drawing the roll wear distribution curve W1(y);

[0062] S42: Calculate the crack depth of the roll and draw the overall fatigue distribution curve T1(y) of the roll;

[0063] S43: Taking the weighted sum of the fatigue crack distribution curve T1(y) and the wear distribution curve W1(y) of the rolling mill roller.

[0064] Furthermore, the expression for the inter-roller wear between the rollers is as follows:

[0065]

[0066] The expression of wear between the work roll and the workpiece is as follows:

[0067]

[0068] Where y is the transverse coordinate of the roll and strip unit; Q ro (y), Q rp (y) are rolling L t The wear of the roll and the work roll when the length of the strip is less than 0.05 mm; q(y) is the distribution of the contact pressure between the rolls, kN / mm; D is the roll diameter, mm; R 10 ,R 20 are the working radius of the two contacting rollers, mm; R1(y), R2(y) are the load radius distribution values of the two rollers, mm; R 1c (y) is the original grinding radius distribution value of roller 1; R 2c (y) is the original radius of roller 2, mm; ΔR 1t (y),ΔR 2t (y) are the radial distribution values of the thermal crown of the two rolls; q′(y) is the distribution of rolling pressure, kN / mm; D s is the working roll diameter, mm; C(y) is a function related to the lateral flow of metal in the roll gap; h c is the average thickness of the strip deformation zone.

[0069] Furthermore, the crack depth of the roller is calculated by numerically inverting the crack depth of the roller under the current rolling kilometer using the following formula:

[0070]

[0071] Where N is the number of stress cycles; a is the crack depth, mm; E is the elastic modulus of the roller surface material, gPa; ε f is the fracture ductility; ΔK is the stress intensity factor range Δσ is the amplitude of cyclic stress change, mpa; ΔK th is the roller fatigue threshold; ΔK th =(8.5-0.0003σ 0.2 )(1-R) γ ,σ 0.2 is the yield limit of the roller surface material, mPa; γ is the material determination constant; a0 is the initial crack depth of the roller, and a1 is the extension length of the crack generated after the roller has rolled for L kilometers, mm.

[0072] Furthermore, the following formula is used to perform weighted summation of the fatigue crack distribution curve T1(y) and the wear distribution curve W1(y) of the rolling mill.

[0073] F1=0.63∑T1(y)+0.37∑W1(y)

[0074] Furthermore, the working parameters of the rolling mill include the diameter D of the working roll. S , the diameter D of the first intermediate roller P , diameter D of the second intermediate roller JK , diameter D of the support roller CD , the roller body length L of the working roller S , the first intermediate roller's roller length L P , the roller length L of the second intermediate roller JK , Roller length L of the support roller CD ; Yield limit of roller surface material σ 0.2 ; Material determination constant γ; Cyclic stress change amplitude Δσ.

[0075] A device for calculating the equivalent rolling kilometers of a twenty-high rolling mill roll, characterized by comprising:

[0076] Acquisition module: used to obtain equipment specifications of the rolling mill and characteristic parameters of the roll surface material;

[0077] Calculation module 1: used to select the target process parameter C0 of the rolling mill and calculate the inter-roll pressure and rolling pressure distribution of each roll of the rolling mill corresponding to the target process parameter based on the working parameters of the rolling mill;

[0078] Calculation module II: used to obtain the actual process parameters C1 of the rolling mill, and calculate the inter-roller pressure and rolling pressure distribution of each roll of the rolling mill corresponding to the actual process parameters and the current actual rolling mileage based on the working parameters of the rolling mill;

[0079] Calculation module III: Under the actual process parameters C1 of the rolling mill and the corresponding rolling mileage L1, the weighted sum F1 of the fatigue crack distribution curve and the wear distribution curve is calculated based on the inter-roller pressure and rolling pressure of each roll corresponding to the actual process parameters and the current actual rolling mileage;

[0080] Calculation module IV: Under the target process parameters C0, set the iteration initial value L, iteration step length ΔL, iteration variable initial value k = 0, and when the rolling kilometers are L + k * ΔL, calculate the fatigue crack distribution curve T0(y) and wear distribution curve W0(y) of the roll based on the inter-roller pressure and rolling pressure of each roll corresponding to the target process parameters, and then calculate F0 by weighting them;

[0081] Judgment module: judge |F1-F0|<threshold ε, if the judgment result is yes, go to step S7, if the judgment result is no, set k+1, go to step calculation module IV;

[0082] Calculation module V: Calculates the equivalent rolling kilometers required for the rolling mill to produce equivalent fatigue cracks and wear under the target process parameters C0.

[0083] A computer device includes: a processor and a memory, wherein the memory stores a program module, and the program module runs on the processor to implement any one of the methods described above.

[0084] Example 1

[0085] like Figure 1 As shown, the present invention provides a method for calculating the equivalent rolling kilometers of a twenty-high rolling mill roll, and the implementation steps are as follows:

[0086] (1) In step (A), collect the equipment specifications and roll surface material characteristic parameters of the rolling mill. Mainly including: diameter D of the working roll, first intermediate roll, second intermediate roll, and backup roll S =80mm,D P =138mm,D JK =235mm,D CD =406.4mm; Roller length L of working roll, first intermediate roll, second intermediate roll and backup roll S =1677mm,L P =1500mm,L JK =1450mm,L CD =1344m; yield strength of roller surface material σ 0.2 =1 MPa; material determination constant γ = 0.95; cyclic stress change amplitude Δσ = 1050 MPa;

[0087] (2) In step (B), the target process parameters C0 of the rolling mill and the inter-roller pressure and rolling pressure distribution of each roll calculated in advance based on the working parameters of the rolling mill are selected. These parameters mainly include: the front and rear tensions of the strip T0 = 20t, T1 = 3.5t; the inlet and outlet thicknesses of the strip h0 = 2.20mm, h1 = 1.34mm; the strip width B = 1200mm; the yield strength of the strip K = 823mPa; the total rolling pressure P = 517t; the elastic modulus E = 195gPa; the Poisson's ratio v = 0.28; that is, C0 = {T0, T1, h0, h1, B, K, P, E, v};

[0088] (3) In step (C), the actual process parameters C1 of the rolling mill and the inter-roller pressure and rolling pressure distribution of each roller calculated in advance based on the working parameters of the rolling mill, as well as the current actual rolling mileage L1 are collected. The process characteristic parameters mainly include: the front and rear tensions of the strip T0 = 20t, T1 = 3.5t; the inlet and outlet thicknesses of the strip h0 = 2.20mm, h1 = 1.37mm; the strip width B = 1110mm; the yield strength of the strip K = 702.48mpa; the total rolling pressure P = 517.46t; the elastic modulus E = 186gpa; the Poisson's ratio v = 0.28; that is, C1 = {T0, T1, h0, h1, B, K, P, E, v} and the actual rolling mileage L1 = 4.43km;

[0089] (4) In step (D), under the actual process parameters C1, the fatigue and wear distribution curves are weighted and summed based on the inter-roller pressure and rolling pressure of each roll corresponding to the actual process parameters and the current actual rolling mileage. The fatigue crack distribution curve T1(y) and wear distribution curve W1(y) generated by the roll when rolling the corresponding mileage L1 under the actual process parameters C1 are calculated, and the fatigue crack distribution curve and wear distribution curve are weighted and summed. The working roll is used as an example below, and the algorithm for other rolls is similar.

[0090] (D1) Calculate the wear of the working roll. Figure 2 , it can be seen that work roll wear can be divided into wear between the work roll and the first intermediate roll, and wear between the work roll and the workpiece. The wear loss in each area is calculated segment by segment. Then, based on the inter-roll pressure and the lateral distribution of rolling pressure, the work roll wear curve is calculated, and finally, the work roll wear distribution curve W1(y) is plotted.

[0091] Inter-roll wear between rolls

[0092] Wear between work roll and rolled product

[0093] Where y is the transverse coordinate of the roll and strip unit; Q ro(y), Q rp (y) are rolling L t The wear of the roll and the work roll when the length of the strip is less than 0.05 mm; q(y) is the distribution of the contact pressure between the rolls, kN / mm; D is the roll diameter, mm; R 10 ,R 20 is the working radius of the two contacting rollers, mm; R1(y), R2(y) are the load radius distribution values of the two rollers; R 1c (y) is the original grinding radius distribution value of roller 1; R 2c (y) is the original radius of roller 2, mm; ΔR 1t (y),ΔR 2t (y) is the radial distribution value of the thermal crown of the two rolls; q′(y) is the distribution of rolling pressure, kN / mm; D s is the working roll diameter, mm; C(y) is a function related to the lateral flow of metal in the roll gap; h c is the average thickness of the strip deformation zone.

[0094] (D2) Calculate the crack depth of the working roll. First, numerical methods can be used to inversely calculate the roll crack depth at the current rolling mileage. Under the current rolling mileage and the initial state a0 of the roll, the current roll crack depth is set to a = a0 + kΔa (k is the iteration variable, Δa is the iteration step size). The value of k is continuously increased so that the calculation result approaches the actual rolling mileage. The crack depth can be calculated, and then the fatigue life of the roll can be obtained. Based on the lateral distribution of the inter-roll pressure and the rolling pressure, the fatigue curve of each area is obtained, and the overall fatigue distribution curve T1(y) of the working roll is plotted.

[0095]

[0096] Where N is the number of stress cycles; a is the crack depth, mm; E is the elastic modulus of the roller surface material, gPa; ε f is the fracture ductility; ΔK is the stress intensity factor range Δσ is the amplitude of cyclic stress change, mpa; ΔK th =(8.5-0.0003σ 0.2 )(1-R) γ ; σ 0.2 is the yield strength of the roller surface material, mPa; γ is the material determination constant; a0 and a1 are the initial crack depth of the roller and the extension length of the crack generated after the roller has rolled for L kilometers, respectively, in mm;

[0097] (D3) Weighted summation of fatigue and wear distribution curves. Weighted summation of the roller's fatigue crack distribution curve T1(y) and wear distribution curve W1(y): F1 = 0.63∑T1(y) + 0.37∑W1(y);

[0098] (5) In step (E), the initial value of the iteration variable is given. Set the initial value of the iteration L = 4.40 km, the iteration step length ΔL = 0.01 km, and the initial value of the iteration variable k = 0;

[0099] (6) In step (F), under the target process parameter C0, the fatigue and wear distribution curves are weighted and summed. Under the target process parameter C0, when the rolling kilometer number L+k*ΔL, the fatigue crack distribution curve T0(y) and the wear distribution curve W0(y) of the roll are calculated according to the formula in steps (D1-D3), and then weighted calculation is performed, F0=0.63∑T0(y)+0.37∑W(y);

[0100] (7) In step (G), determine whether |F1-F0| < ε. If the determination result is yes, proceed to step (H). If the determination result is no, set k + 1 and proceed to step (F).

[0101] (8) In step (H), the equivalent rolling kilometers of the rollers are output. Calculate the equivalent rolling kilometers required for the rollers to produce equivalent fatigue cracks and wear under the target process parameters C0: L0 = L + k * ΔL = 6.93 km;

[0102] Example 2

[0103] like Figure 1 As shown, the present invention provides a method for calculating the equivalent rolling kilometers of a twenty-high rolling mill roll, and the implementation steps are as follows.

[0104] (1) In step (A), select the equipment specifications of the rolling mill and the characteristic parameters of the roll surface material. Mainly including: the diameter D of the working roll, the first intermediate roll, the second intermediate roll, and the backup roll S =80mm,D P =138mm,D JK =235mm,D CD =406.4mm; Roller length L of working roll, first intermediate roll, second intermediate roll and backup roll S =1677mm,L P =1500mm,L JK =1450mm,L CD =1344m; yield strength of roller surface material σ 0.2 =1 MPa; material determination constant γ = 0.95; cyclic stress change amplitude Δσ = 1050 MPa;

[0105] (2) In step (B), the target process parameters C0 of the rolling mill and the inter-roller pressure and rolling pressure distribution of each roll calculated in advance based on the working parameters of the rolling mill are selected. These parameters mainly include: the front and rear tensions of the strip T0 = 20t, T1 = 3.5t; the inlet and outlet thicknesses of the strip h0 = 2.30mm, h1 = 1.49mm; the strip width B = 1030mm; the yield strength of the strip K = 669.62mPa; the total rolling pressure P = 496.58t; the elastic modulus E = 200gPa; the Poisson's ratio v = 0.27; that is, C0 = {T0, T1, h0, h1, B, K, P, E, v};

[0106] (3) In step (C), the actual process parameters C1 of the rolling mill and the inter-roller pressure and rolling pressure distribution of each roll calculated in advance based on the working parameters of the rolling mill, as well as the current actual rolling mileage L1 are collected. The process characteristic parameters mainly include: the front and rear tensions of the strip T0 = 20t, T1 = 3.5t; the inlet and outlet thicknesses of the strip h0 = 2.30mm, h1 = 1.38mm; the strip width B = 1025mm; the yield strength of the strip K = 1037.95mpa; the total rolling pressure P = 448.98t; the elastic modulus E = 200gpa; the Poisson's ratio v = 0.27; that is, C1 = {T0, T1, h0, h1, B, K, P, E, v} and the actual rolling mileage L1 = 3.64km;

[0107] (4) In step (D), under the actual process parameters C1, the fatigue and wear distribution curves are weighted and summed based on the inter-roller pressure and rolling pressure of each roll corresponding to the actual process parameters and the current actual rolling mileage. The fatigue crack distribution curve T1(y) and wear distribution curve W1(y) generated by the roll when rolling the corresponding mileage L1 under the actual process parameters C1 are calculated, and the fatigue crack distribution curve and wear distribution curve are weighted and summed. The working roll is used as an example below, and the algorithm for other rolls is similar.

[0108] (D1) Calculate the wear of the working roll. Figure 2 , it can be seen that work roll wear can be divided into inter-roll wear between the work roll and the first intermediate roll, and wear between the work roll and the workpiece. The wear loss in each area is calculated segment by segment. Then, based on the inter-roll pressure and the lateral distribution of rolling pressure, the work roll wear curve is calculated, and finally, the work roll wear distribution curve W1(y) is plotted.

[0109] Inter-roll wear between rolls

[0110] Wear between work roll and rolled product

[0111] Where y is the transverse coordinate of the roll and strip unit; Qro (y), Q rp (y) are rolling L t The wear of the roll and the work roll when the length of the strip is less than 0.05 mm; q(y) is the distribution of the contact pressure between the rolls, kN / mm; D is the roll diameter, mm; R 10 ,R 20 is the working radius of the two contacting rollers, mm; R1(y), R2(y) are the load radius distribution values of the two rollers; R 1c (y) is the original grinding radius distribution value of roller 1; R 2c (y) is the original radius of roller 2, mm; ΔR 1t (y),ΔR 2t (y) is the radial distribution value of the thermal crown of the two rolls; q′(y) is the distribution of rolling pressure, kN / mm; D s is the working roll diameter, mm; C(y) is a function related to the lateral flow of metal in the roll gap; h c is the average thickness of the strip deformation zone.

[0112] (D2) Calculate the crack depth of the working roll. The cracks of the roll mainly occur in the crack propagation stage. The crack depth of the roll under the current rolling mileage can be inversely calculated by numerical methods. Under the current rolling mileage and the initial state of the roll a0, the current roll crack depth a=a0+kΔa (k is the iteration variable, Δa is the iteration step size) is set. The value of k is continuously increased to make the calculation result close to the actual rolling mileage. The crack depth can be obtained, and then the fatigue life of the roll can be obtained. Then, according to the lateral distribution of the inter-roller pressure and the rolling pressure, the fatigue curve of each area is obtained, and the overall fatigue distribution curve T1(y) of the roll is drawn;

[0113]

[0114] Where N is the number of stress cycles; a is the crack depth, mm; E is the elastic modulus of the roller surface material, gPa; ε f is the fracture ductility; ΔK is the stress intensity factor range Δσ is the amplitude of cyclic stress change, mpa; ΔK th =(8.5-0.0003σ 0.2 )(1-R) γ ; σ 0.2 is the yield strength of the roller surface material, mPa; γ is the material determination constant; a0 and a1 are the initial crack depth of the roller and the extension length of the crack generated after the roller has rolled for L kilometers, respectively, in mm;

[0115] (D3) Weighted summation of fatigue and wear distribution curves. Weighted summation of the roller's fatigue crack distribution curve T1(y) and wear distribution curve W1(y): F1 = 0.63∑T1(y) + 0.37∑W1(y);

[0116] (5) In step (E), the initial value of the iteration variable is given. Set the initial value of the iteration L = 3.50 km, the iteration step length ΔL = 0.01 km, and the initial value of the iteration variable k = 0;

[0117] (6) In step (F), under the target process parameter C0, the fatigue and wear distribution curves are weighted and summed. Under the target process parameter C0, when the rolling kilometer number L+k*ΔL, the fatigue crack distribution curve T0(y) and the wear distribution curve W0(y) of the roll are calculated according to the formula in steps (D1-D3), and then weighted calculation is performed, F0=0.63∑T0(y)+0.37∑W(y);

[0118] (7) In step (G), determine whether |F1-F0| < ε. If the determination result is yes, proceed to step (H). If the determination result is no, set k + 1 and proceed to step (F).

[0119] (8) In step (H), the equivalent rolling kilometers of the rollers are output. The equivalent rolling kilometers required to produce equivalent fatigue cracks and wear of the rollers under the target process parameters C0 are calculated as L0 = L + k * ΔL = 4.52 km.

[0120] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for calculating the equivalent rolling kilometers of a twenty-high rolling mill roll, characterized in that: The following steps are involved: S1: Obtain equipment specifications of the rolling mill and characteristic parameters of the roll surface material; S2: Selecting the target process parameter C0 of the rolling mill and calculating the inter-roller pressure and rolling pressure distribution of each roll of the rolling mill corresponding to the target process parameter based on the working parameters of the rolling mill; S3: obtaining the actual process parameters C1 of the rolling mill, and calculating the inter-roller pressure and rolling pressure distribution of each roll of the rolling mill corresponding to the actual process parameters and the current actual rolling mileage based on the working parameters of the rolling mill; S4: Under the actual process parameters C1 of the rolling mill and when rolling the corresponding mileage L1, a weighted sum F1 of the fatigue crack distribution curve and the wear distribution curve is calculated based on the inter-roller pressure and rolling pressure of each roll corresponding to the actual process parameters and the current actual rolling mileage; S5: Set the iteration initial value L; S6: Under the target process parameters C0, the iteration step length ΔL, the initial value of the iteration variable k=0, and the rolling mileage L+k*ΔL, the fatigue crack distribution curve T0(y) and the wear distribution curve W0(y) of the roll are calculated based on the inter-roller pressure and rolling pressure of each roll corresponding to the target process parameters, and then the weighted calculation F0 is performed; S7: Determine whether |F1-F0| is less than the threshold ε. If the determination result is yes, proceed to step S7. If the determination result is no, set k+1 and proceed to step S6. S8: Calculate the equivalent rolling kilometers L0=L+k*ΔL required for the rolling mill to produce equivalent fatigue cracks and wear on the rolls under the target process parameters C0.

2. The method for calculating the equivalent rolling kilometers of a twenty-high mill roll according to claim 1, wherein: The calculation process of the weighted sum F1 of the fatigue crack distribution curve and the wear distribution curve based on the actual process parameters C1 of the rolling mill and the corresponding rolling mileage L1, based on the inter-roller pressure and rolling pressure distribution of each roll corresponding to the actual process parameters and the current actual rolling mileage, is as follows: S41: dividing the mill roll wear into inter-roller wear and wear between the roll and the workpiece, dividing the wear of each roll into several sections, calculating the wear amount of each section in sections, then calculating the wear curve of each section based on the inter-roller pressure and the lateral distribution of the rolling pressure, and finally drawing the roll wear distribution curve W1(y); S42: Calculate the crack depth of the roll and draw the overall fatigue distribution curve T1(y) of the roll; S43: Taking the weighted sum of the fatigue crack distribution curve T1(y) and the wear distribution curve W1(y) of the rolling mill roller.

3. The method for calculating the equivalent rolling kilometers of a twenty-high mill roll according to claim 2, wherein: The expression for the inter-roller wear between the rolls is as follows: The expression of wear between the work roll and the workpiece is as follows: Where y is the transverse coordinate of the roll and strip unit; Q ro (y), Q rp (y) are rolling L t The wear of the roll and the work roll when the length of the strip is less than 100 mm; q(y) is the distribution of the contact pressure between the rolls; D is the roll diameter; R 10 ,R 20 are the working radius of the two contacting rollers; R1(y), R2(y) are the load radius distribution values of the two rollers; R 1c (y) is the original grinding radius distribution value of roller 1; R 2c (y) is the original radius of roller 2; ΔR 1t (y),ΔR 2t (y) are the radial distribution values of the thermal crown of the two rolls; q′(y) is the distribution of rolling pressure; D s is the working roll diameter; C(y) is a function related to the lateral flow of metal in the roll gap; h c is the average thickness of the strip deformation zone.

4. The method for calculating the equivalent rolling kilometers of a twenty-high mill roll according to claim 1, wherein: The crack depth of the roller is calculated by numerically inversely calculating the crack depth of the roller under the current rolling kilometer using the following formula: Where N is the number of stress cycles; a is the crack depth; E is the elastic modulus of the roller surface material; ε f is the fracture ductility; ΔK is the stress intensity factor range; Δσ is the cyclic stress change amplitude; ΔK th is the roller fatigue threshold; σ 0.2 is the yield limit of the roller surface material; γ is the material determination constant; a0 is the initial crack depth of the roller; a1 is the extension length of the crack generated after the roller has rolled for L kilometers.

5. The method for calculating the equivalent rolling kilometers of a twenty-high mill roll according to claim 1, wherein: The following formula is used to weight the sum of the fatigue crack distribution curve T1(y) and the wear distribution curve W1(y) of the rolling mill. F1=0.63∑T1(y)+0.37∑W1(y) 6. The method for calculating the equivalent rolling kilometers of a twenty-high mill roll according to claim 1, wherein: The working parameters of the rolling mill include the diameter D of the working rolls. S , the diameter D of the first intermediate roller P , diameter D of the second intermediate roller JK , diameter D of the support roller CD , the roller length L of the working roller S , the first intermediate roller's roller length L P , the roller length L of the second intermediate roller JK , Roller length L of the support roller CD ; Yield limit of roller surface material σ 0.2 ; Material determination constant γ; Cyclic stress change amplitude Δσ.

7. A device for calculating the equivalent rolling kilometers of a twenty-high rolling mill roll, characterized in that: include: Acquisition module: used to obtain equipment specifications of the rolling mill and characteristic parameters of the roll surface material; Calculation module 1: used to select the target process parameter C0 of the rolling mill and calculate the inter-roll pressure and rolling pressure distribution of each roll of the rolling mill corresponding to the target process parameter based on the working parameters of the rolling mill; Calculation module II: used to obtain the actual process parameters C1 of the rolling mill, and calculate the inter-roller pressure and rolling pressure distribution of each roll of the rolling mill corresponding to the actual process parameters and the current actual rolling mileage based on the working parameters of the rolling mill; Calculation module III: Under the actual process parameters C1 of the rolling mill and the corresponding rolling mileage L1, the weighted sum F1 of the fatigue crack distribution curve and the wear distribution curve is calculated based on the inter-roller pressure and rolling pressure of each roll corresponding to the actual process parameters and the current actual rolling mileage; Calculation module IV: Under the target process parameters C0, set the iteration initial value L, iteration step length ΔL, iteration variable initial value k = 0, and when the rolling kilometers are L + k * ΔL, calculate the fatigue crack distribution curve T0(y) and wear distribution curve W0(y) of the roll based on the inter-roller pressure and rolling pressure of each roll corresponding to the target process parameters, and then calculate F0 by weighting them; Judgment module: judge |F1-F0|<threshold ε, if the judgment result is yes, go to step S7, if the judgment result is no, set k+1, go to step calculation module IV; Calculation module V: Calculates the equivalent rolling kilometers required for the rolling mill to produce equivalent fatigue cracks and wear under the target process parameters C0.

8. A computer device comprising: A processor and a memory, wherein the memory stores a program module, wherein the program module runs on the processor to implement the method according to any one of claims 1 to 6.

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