Method for forecasting thickness out-of-tolerance rate of outlet of certain rack of five-rack cold continuous rolling unit

Abstract

The invention relates to a method for forecasting the thickness out-of-tolerance rate of an outlet of a certain rack of a five-rack cold continuous rolling unit. The method comprises the following steps: A) setting rolling parameters and equipment parameters of front and rear racks; B) judging igt; 1, if igt; if i is equal to 1, skipping to C), if i is equal to 1, enabling vi-1 to be equal to v0 and skipping to F), C) calculating a forward slip value fi-1s of the (i-1) th rack, D) calculating a rolling torque Mi-1 of the (i-1) th rack, E) calculating an outlet rolling speed vi-1 of the (i-1) th rack, F) calculating a forward slip value fiis of the ith rack, G) calculating a rolling torque Mi of the ith rack, H) calculating an outlet rolling speed vi of the ith rack, I) calculating an outlet thickness out-of-tolerance rate e of the ith rack. According to the method, the outlet thickness out-of-tolerance rate prediction value of a certain rack of the five-rack cold continuous rolling unit can be obtained by substituting the obtained inlet and outlet rolling speeds of the racks into the established outlet thickness out-of-tolerance rate model according to the field production condition of the cold-rolled strip steel.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of five-stand tandem cold rolling mill outlet thickness control, in particular to a method for predicting the thickness deviation rate of the outlet of a certain stand of a five-stand tandem cold rolling mill. BACKGROUND

[0002] In recent years, with the rapid development of economy, the competition in the steel market is becoming increasingly fierce, and domestic steel products also need higher standards. Steel companies also need to update production technology to reduce costs while obtaining better products and stabilize their position in market competition. An important quality standard for cold-rolled products is thickness accuracy, so thickness control is the core technology of the strip rolling field. The establishment of the thickness deviation rate model can more accurately predict the thickness fluctuation at the outlet of the rolling mill, so in order to improve the quality of cold-rolled products, it is necessary to fully consider the actual production situation of the cold rolling site and the characteristics of the five-stand tandem cold rolling mill to develop a method for predicting the thickness deviation rate of the outlet of a certain stand of a five-stand tandem cold rolling mill.

[0003] Prior art comparison

[0004] Invention patent: Thickness control optimization method for ultra-high strength steel cold rolling mill (application number: CN202210970376.X), the present application discloses a thickness control optimization method for ultra-high strength steel cold rolling mill, which fully considers the influence of factors such as incoming material performance and incoming material thickness on roll gap adjustment amount, establishes a thickness control optimization model by studying the influence of roll gap adjustment amount on rolling mill outlet thickness and thickness deviation rate, and accordingly optimizes to ensure the uniformity of the rolling mill outlet thickness in the longitudinal direction, reduces the length of the strip longitudinal thickness difference and the amount of strip repair.

[0005] Invention patent: Thickness control compensation method for ultra-high strength steel cold rolling acceleration and deceleration process (application number: CN202210966272.1), the present application discloses a thickness control compensation method for ultra-high strength steel cold rolling acceleration and deceleration process, which completes the optimization evaluation of the set front tension and the set rear tension by setting an evaluation model based on the strip outlet thickness deviation rate and combining the historical actual values of the rolling force of each stand, the inlet speed of each stand, the outlet speed of each stand, the inlet thickness of each stand, and the outlet thickness of each stand. According to the evaluation results, the front tension and rear tension set values are optimized, and the thickness control compensation of the ultra-high strength steel cold rolling acceleration and deceleration process is completed. The thickness control compensation method for ultra-high strength steel cold rolling acceleration and deceleration process according to the present application establishes a multi-factor based thickness control compensation optimization based on the actual multi-dimensional data and the set evaluation model.

[0006] Invention patent: Roll gap adjustment method for ultra-high strength steel cold rolling process (application number: CN202311116003.7)

[0007] The application is a roll gap adjusting method suitable for ultra-high strength steel cold continuous rolling process, comprising the following steps: firstly, establishing an ultra-high strength steel thickness overproof prediction model, calculating the n and n+1 thickness overproof prediction values γ<subgt;i,n、γ<subgt;i,n+1of the i incoming material strip; secondly, establishing a roll gap adjusting amount prediction model, calculating the rolling mill roll gap adjusting amount ΔS<subgt;i, establishing a best roll gap adjusting amount target function in the rolling process; based on the optimization method, the best roll gap adjusting amount target function is solved to obtain the best roll gap adjusting amount. The method can overcome the full length thickness difference fluctuation and head and tail thickness overproof in the process of rolling ultra-high strength steel by the traditional automatic thickness control system of the cold continuous rolling mill set, greatly improving the thickness control precision of the ultra-high strength steel. SUMMARY

[0008] The application fully combines the equipment characteristics of the five-stand cold continuous rolling mill set, and under the condition of a certain rolling power, the inlet and outlet rolling speeds of a stand are obtained by rolling force, the inlet and outlet rolling speeds of the stand are substituted into the established outlet thickness overproof rate model to obtain the outlet thickness overproof rate prediction value of the five-stand cold continuous rolling mill set.

[0009] The five-stand cold continuous rolling mill set outlet thickness overproof rate prediction method is based on the equipment characteristics of the five-stand cold continuous rolling mill set, the inlet and outlet cold rolling speeds are calculated by substituting the rolling force set value of a stand, and the overproof rate is obtained by using the inlet and outlet rolling speeds, the outlet thickness overproof rate prediction of the five-stand cold continuous rolling mill set is realized, and the specific technical scheme is as follows:

[0010] A) Set rolling parameters and front and rear stand equipment parameters, mainly including: the i-1 stand strip inlet thickness set value H i-1 ; the i-1 stand strip outlet thickness set value h i-1 ; the i stand strip inlet thickness set value H i ; the i stand strip outlet thickness set value h i ; the 1st stand inlet rolling speed v0; the i-1 stand deformation resistance K i-1 ; the i-1 stand front unit tension σ i-1前 ; the i-1 stand rear unit tension σ i-1后 ; the i-1 stand work roll diameter D i-1 ; the i-1 stand friction coefficient μ i-1 ; the i-1 stand rolling force set value P i-1 ; the i stand rolling force set value P i ; the i stand deformation resistance K i ; the i stand front unit tension σ i前 ; the i stand rear unit tension σi后 ; incoming strip width B; i-th stand work roll diameter D i ; i-th stand friction coefficient μ i ; elastic modulus E; Poisson's ratio v; i-1-th stand rolling power W i-1 ; i-1-th stand motor efficiency η i-1 ; i-th stand rolling power W i ; i-th stand motor efficiency η i .

[0011] B) if i > 1, go to C), if i = 1, let v i-1 = v0and go to F).

[0012] C) calculate i-1-th stand front slip value f i-1s .

[0013]

[0014] where: R' i-1 = i-1-th stand flattening radius, expressed by the following equation:

[0015]

[0016] D) calculate i-1-th stand rolling torque M i-1 .

[0017]

[0018] where: ξ i-1 = i-1-th stand equivalent tension influence coefficient, ξ i-1 = 0.3σ i-1前 + 0.7σ i-1后 ;

[0019] Q i-1G = i-1-th stand outer friction influence coefficient, expressed by the following equation:

[0020]

[0021] r i-1 = i-1-th stand pass reduction rate,

[0022] E) calculate i-1-th stand exit rolling speed v i-1 .

[0023]

[0024] F) calculate i-th stand front slip value f is .

[0025]

[0026] wherein R' i — the flattening radius of the i-th stand, expressed by the following formula:

[0027]

[0028] G) calculating the rolling moment M of the i-th stand i .

[0029]

[0030] wherein ξ i — the equivalent tension influence coefficient of the i-th stand, ξ i = 0.3σ i前 + 0.7σ i后 ;

[0031] Q iG — the outer friction influence coefficient of the i-th stand, expressed by the following formula:

[0032]

[0033] r i — the pass reduction rate of the i-th stand,

[0034] H) calculating the rolling speed v of the i-th stand outlet i .

[0035]

[0036] I) calculating the thickness deviation e of the i-th stand outlet.

[0037]

[0038] Compared with the prior art, the present application has the following advantages: (1) the present application can, according to the on-site production conditions of the cold-rolled strip, fully combine the equipment characteristics of the five-stand cold continuous rolling mill, and under the condition of giving a certain rolling power, obtain the inlet and outlet rolling speeds of a certain stand by the rolling force setting value, and by substituting the obtained inlet and outlet rolling speeds of the stand into the outlet thickness deviation model, the outlet thickness deviation prediction value of the five-stand cold continuous rolling mill is obtained; (2) the present application can more accurately predict the outlet thickness deviation of a certain stand of the five-stand cold continuous rolling mill before production, and provide the rolling parameter adjustment reference for enterprises, so as to improve the product quality of the rolled strip and bring greater economic benefits. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 It is a flow chart of the present application for predicting the outlet thickness deviation of a certain stand of a five-stand cold continuous rolling mill. DETAILED DESCRIPTION

[0040] Taking the first rack and the second rack of a five-rack continuous cold rolling mill as an example, combining the rolling parameters and the front and rear rack equipment parameters, Figure 1 , the five-rack continuous cold rolling mill rack outlet thickness deviation rate prediction method is described in detail.

[0041] Example 1:

[0042] First, in step A), set the rolling parameters and the front and rear rack equipment parameters, mainly including: the first rack strip inlet thickness set value H1; the first rack strip outlet thickness set value h1; the first rack inlet rolling speed v0; the first rack rolling force set value P1; the first rack deformation resistance K1; the first rack front unit tension σ 1前 ; the first rack rear unit tension σ 1后 ; incoming width B; the first rack work roll diameter D1; the first rack friction coefficient μ1; elastic modulus E; Poisson's ratio v; the first rack rolling power W1; the first rack motor efficiency η1.

[0043] Table 1 Rolling parameters and front and rear rack equipment parameters

[0044] Name 1st stand Rolling force set value / N 8400000 1st stand entry rolling speed / (m / min) 150 Strip entry thickness set value / mm 3 Strip exit thickness set value / mm 1.8 Deformation resistance / MPa 700 Front unit tension / MPa 150 Back unit tension / MPa 100 Material width / mm 950 Work roll diameter / mm 404 Friction coefficient 0.04 Elastic modulus / MPa 210000 Poisson's ratio 0.3 Rolling power / kW 4400 Motor efficiency / % 80

[0045] Then in step B), judge i>1, i=1, then v i-1 =v0 and jump to F).

[0046] Then in step F), calculate the first rack front slip value f 1s .

[0047]

[0048] In the formula: R'1 is the first rack flattening radius, which is represented by the following formula:

[0049]

[0050] The calculation gives f 1s =0.0019.

[0051] Then in step G), calculate the first rack rolling torque M1.

[0052]

[0053] In the formula: ξ1 is the first rack equivalent tension influence coefficient, ξ1=0.3σ 1前 +0.7σ 1后 ;

[0054] Q 1G is the first rack external friction influence coefficient, which is represented by the following formula:

[0055]

[0056] r1— first stand pass reduction rate,

[0057] M1= 175970.4 N-m is calculated

[0058] Then in step H), the first stand exit rolling speed v1is calculated.

[0059]

[0060] v1= 242.9 m / min is calculated.

[0061] Finally in step I), the first stand exit thickness tolerance e is calculated.

[0062]

[0063] r1— first stand pass reduction rate,

[0064] e = 2.924% is calculated.

[0065] Example 2:

[0066] First in step A), the rolling parameters and front and rear stand equipment parameters are set, mainly including: the first stand strip steel inlet thickness set value H1; the first stand strip steel outlet thickness set value h1; the first stand inlet rolling speed v0; the first stand rolling force set value P1; the first stand deformation resistance K1; the first stand front unit tension σ 1前 ; the first stand rear unit tension σ 1后 ; incoming material width B; the first stand work roll diameter D1; the first stand friction coefficient μ1; elastic modulus E; Poisson's ratio v; the first stand rolling power W1; the first stand motor efficiency η1; the second stand strip steel inlet thickness set value H2; the second stand strip steel outlet thickness set value h2; the second stand rolling force set value P2; the second stand deformation resistance K2; the second stand front unit tension σ 2前 ; the second stand rear unit tension σ 2后 ; the second stand work roll diameter D2; the second stand friction coefficient μ2; the second stand rolling power W2; and the second stand motor efficiency η2.

[0067] Table 2 Rolling parameters and front and rear stand equipment parameters

[0068] Name 1st stand 2nd stand Rolling force set value / N 8400000 8000000 1st stand entry rolling speed / (m / min) 150 150 Strip entry thickness set value / mm 3 1.8 Strip exit thickness set value / mm 1.8 1 Deformation resistance / MPa 700 760 Front unit tension / MPa 150 150 Back unit tension / MPa 100 100 Material width / mm 950 950 Work roll diameter / mm 404 400 Friction coefficient 0.04 0.05 Elastic modulus / MPa 210000 210000 Poisson's ratio 0.3 0.3 Rolling power / kW 4400 6200 Motor efficiency / % 80 80

[0069] Then in step B), it is determined that i > 1, i = 2 > 1, then jump to C).

[0070] Then in step C), the front slip value f of the 1st stand is calculated 1s .

[0071]

[0072] wherein: R'1 - the flattening radius of the 1st stand, expressed by the following formula:

[0073]

[0074] The f is calculated as follows: 1s = 0.0019.

[0075] Then in step D), the rolling moment M1 of the 1st stand is calculated.

[0076]

[0077] wherein: ξ1 - the equivalent tension influence coefficient of the 1st stand, ξ1 = 0.3σ 1前 + 0.7σ 1后 ;

[0078] Q 1G - the outer friction influence coefficient of the 1st stand, expressed by the following formula:

[0079]

[0080] r1 - the pass reduction rate of the 1st stand,

[0081] The M1 is calculated as follows:

[0082] Then in step E), the exit rolling speed v1 of the 1st stand is calculated.

[0083]

[0084] The v1 is calculated as follows:

[0085] Then in step F), the front slip value f of the 2nd stand is calculated 2s .

[0086]

[0087] wherein: R'2 - the flattening radius of the 2nd stand, expressed by the following formula:

[0088]

[0089] The f is calculated as follows: 2s = 0.037.

[0090] Then in step G), the rolling moment M2 of the 2nd stand is calculated.

[0091]

[0092] wherein: ξ2 is the second housing equivalent tension influence coefficient, ξ2 = 0.3σ 2前 + 0.7σ 2后 ;

[0093] Q 2G is the second housing external friction influence coefficient, which is expressed by the following formula:

[0094]

[0095] r2 is the second housing pass reduction rate,

[0096] M2 = 135871.3 N·m is calculated

[0097] Then in step H), the second housing exit rolling speed v2 is calculated.

[0098]

[0099] v2 = 454.3 m / min is calculated.

[0100] Finally in step I), the second housing exit thickness tolerance e is calculated.

[0101]

[0102] wherein: r2 is the second housing pass reduction rate,

[0103] e = 3.75% is calculated.

[0104] It should be noted that the above examples are not intended to limit the scope of protection of the present application, and equivalent transformations or substitutions made on the basis of the above technical solutions all fall within the scope of protection of the claims of the present application.

Claims

1. A method for predicting the thickness deviation rate at the exit of a certain stand of a five-stand tandem cold rolling mill, characterized in that, The method comprises the following steps: A) setting rolling parameters and front and rear stand equipment parameters, B) If i > 1, jump to C), if i = 1, let v i-1 = v0 and jump to F), C) Calculate the i-1 st rack front slide value f i-1s , D) Calculate the i-1 stand rolling moment M i-1 , E) calculating the i-1 stand exit rolling speed v i-1 , F) Calculate the ith rack front slide value f is , G) Calculate the i-th stand rolling moment M i , H) Calculate the i-th stand exit rolling speed v i , I) calculating the i-th stand exit thickness overrun rate e.

2. The method of predicting the thickness deviation rate at the exit of a certain stand of a five-stand continuous cold rolling mill according to claim 1, characterized in that, A) setting rolling parameters and front and rear stand equipment parameters, mainly including: the set value of the strip thickness at the strip inlet of the i-1 stand H i-1 ; the set value of the strip thickness at the strip outlet of the i-1 stand h i-1 ; the set value of the strip thickness at the strip inlet of the i stand H i ; the set value of the strip thickness at the strip outlet of the i stand h i ; the rolling speed v0 at the inlet of the 1 stand; the deformation resistance K i-1 ; the unit tension σ i-1前 ; the unit tension σ i-1后 ; the work roll diameter D i-1 ; the friction coefficient μ i-1 ; the set value of the rolling force P i-1 ; the set value of the rolling force P i ; the deformation resistance K i ; the unit tension σ i前 ; the unit tension σ i后 ; the work roll diameter D i ; the friction coefficient μ i ; the elastic modulus E; the Poisson's ratio v; the rolling power W i-1 ; the motor efficiency η i-1 ; the rolling power W i ; the motor efficiency η i .

3. The method of predicting the thickness deviation rate at the exit of a certain stand of a five-stand continuous mill set according to claim 1, characterized in that, C) Calculate the i-1 st rack front slide value f i-1s , wherein: R' i-1 - the flattening radius of the i-1stand, expressed by the following formula:

4. The method of predicting the thickness deviation rate at the exit of a certain stand of a five-stand continuous mill set according to claim 1, characterized in that, D) Calculate the i-1 stand rolling moment M i-1 , wherein: ξ i-1 - the equivalent tension influence coefficient of the i-1 st rack, ξ i-1 = 0.3 σ i-1前 + 0.7 σ i-1后 ; Q i-1G - the coefficient of the external friction influence of the i-1 st rack, expressed by the following formula: r i-1 — the i-1 stand pass reduction ratio, 5. The method of predicting the thickness deviation rate at the exit of a certain stand of a five-stand continuous mill set according to claim 1, characterized in that, E) calculating the i-1 stand exit rolling speed v i-1 , 6. The method of predicting the thickness deviation rate at the exit of a certain stand of a five-stand continuous mill set according to claim 1, characterized in that, F) Calculate the ith rack front slide value f is , wherein: R' i - the flattening radius of the i-th stand is expressed by the following equation:

7. The method of predicting the thickness deviation rate at the exit of a certain stand of a five-stand continuous mill set according to claim 1, characterized in that, G) Calculate the rolling moment M of the i-th stand i , wherein: ξ i — the equivalent tension influence coefficient of the i-th rack, ξ i = 0.3σ i前 + 0.7σ i后 ; Q iG - the coefficient of the external friction influence on the i-th stand is expressed by the formula: r i — the i-th pass reduction ratio, 8. The method for predicting the thickness tolerance rate at the outlet of a stand of a five-stand cold rolling mill according to claim 1, characterized in that: H) calculating the i-th stand exit rolling speed v i , 9. The method of predicting the thickness deviation rate at the exit of a certain stand of a five-stand continuous mill set according to claim 1, characterized in that, I) calculating the i-th stand exit thickness overrun rate e,

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