A method for predicting the thickness deviation rate at the exit of a certain stand in a five-stand cold rolling mill.

Abstract

This application relates to a method for predicting the thickness deviation rate at the exit of a certain stand in a five-stand cold rolling mill. The method includes the following steps: A) setting rolling parameters and front and rear stand equipment parameters; B) determining if i>1, and if i>1, proceeding to C); if i=1, then letting v... i‑1 =v0 and jump to F), C) calculate the forward slip value f of the (i-1)th frame. i‑1s D) Calculate the rolling torque M of the (i-1)th stand. i‑1 E) Calculate the exit rolling speed v of the (i-1)th stand. i‑1 , F) Calculate the forward slip value f of the i-th frame is , G) Calculate the rolling torque M of the i-th stand i , H) Calculate the exit rolling speed v of the i-th stand i I) Calculate the thickness deviation rate e at the exit of the i-th stand. This invention can obtain the predicted value of the thickness deviation rate at the exit of a certain stand in a five-stand cold rolling mill by substituting the obtained inlet and outlet rolling speeds of the stand into the established thickness deviation rate model based on the on-site production conditions of cold-rolled strip.

Description

Technical Field

[0001] This invention relates to the field of thickness control at the exit of a five-stand cold rolling mill, and particularly to a method for predicting the thickness deviation rate at the exit of a certain stand in a five-stand cold rolling mill. Background Technology

[0002] In recent years, rapid economic development has intensified competition in the steel market, necessitating higher standards for domestic steel products. Steel companies urgently need to update their production technologies to reduce costs while producing better products, thus securing their market position. Thickness accuracy is a crucial quality standard for cold-rolled products, making thickness control a core technology in strip rolling. Establishing a deviation rate model can accurately predict thickness fluctuations at the mill exit. Therefore, to improve the quality of cold-rolled products, it is essential to fully consider the actual production conditions at the cold rolling mill site and the characteristics of a five-stand cold continuous rolling mill, developing a method suitable for predicting the deviation rate of thickness at the exit of a specific stand in a five-stand cold continuous rolling mill.

[0003] Comparison of existing technologies

[0004] Invention Patent: A method for optimizing the thickness control of ultra-high strength steel in a cold continuous rolling mill (Application No.: CN202210970376.X). This invention discloses a method for optimizing the thickness control of ultra-high strength steel in a cold continuous rolling mill. It fully considers the influence of factors such as incoming material performance and incoming material thickness on the roll gap adjustment amount. By studying the influence of the roll gap adjustment amount on the mill exit thickness and thickness deviation rate, a thickness control optimization model is established. Based on this optimization, the uniformity of the mill exit thickness in the longitudinal direction can be ensured, and the longitudinal thickness difference length of the strip and the amount of strip rework can be reduced.

[0005] Invention Patent: A Thickness Control Compensation Method for Acceleration and Deceleration Processes in Cold Continuous Rolling of Ultra-High Strength Steel (Application No.: CN202210966272.1). This invention discloses a thickness control compensation method for acceleration and deceleration processes in cold continuous rolling of ultra-high strength steel. By establishing an evaluation model based on the strip exit thickness deviation rate, and combining historical actual values ​​of rolling force, entry speed, exit speed, entry thickness, and exit thickness of each stand, the method optimizes the set pre-tension and post-tension. Based on the evaluation results, it optimizes the set values ​​of the pre-tension and post-tension, thereby completing the thickness control compensation for acceleration and deceleration processes in cold continuous rolling of ultra-high strength steel. This invention's thickness control compensation method for acceleration and deceleration processes in cold continuous rolling of ultra-high strength steel establishes a multi-factor-based thickness control compensation optimization based on actual multi-dimensional data and an established evaluation model.

[0006] Invention Patent: A method for adjusting roll gap in the cold continuous rolling process of ultra-high strength steel (Application No.: CN202311116003.7)

[0007] The invention discloses a roll gap adjusting method suitable for the cold continuous rolling process of ultra-high strength steel, comprising the following steps: firstly, establishing an ultra-high strength steel thickness out-of-tolerance prediction model, and calculating the n-th and n+1-th thickness out-of-tolerance rate predicted values γ<subgt;i,n< / subgt; and γ<subgt;i,n+1< / subgt; of the i-th coil incoming strip steel; secondly, establishing a roll gap adjustment amount prediction model, calculating the roll gap adjustment amount ΔS<subgt;i< / subgt; of the rolling mill, and establishing an objective function for the optimal roll gap adjustment amount in the rolling process; solving the objective function for the optimal roll gap adjustment amount based on an optimization method to obtain the optimal roll gap adjustment amount. The method can overcome the full-length thickness difference fluctuation and head and tail thickness out-of-tolerance occurring when the traditional automatic thickness control system of a cold continuous rolling mill rolls ultra-high strength steel, and greatly improves the thickness control precision of ultra-high strength steel. Summary of the Invention

[0008] The invention fully combines the equipment characteristics of a five-stand cold continuous rolling mill, obtains the inlet and outlet rolling speeds of a certain stand through rolling force under the condition of giving a certain rolling power, and substitutes the obtained inlet and outlet rolling speeds of the stand into the established outlet thickness out-of-tolerance rate model to obtain the predicted outlet thickness out-of-tolerance rate of a certain stand of the five-stand cold continuous rolling mill.

[0009] The method for predicting the outlet thickness out-of-tolerance rate of a certain stand of the five-stand cold continuous rolling mill according to the present invention is based on the equipment characteristics of the five-stand cold continuous rolling mill, calculates the inlet and outlet cold rolling speeds of a certain stand by substituting the set rolling force value of the stand, obtains the out-of-tolerance rate by using the inlet and outlet rolling speeds, and realizes the prediction of the outlet thickness out-of-tolerance rate of a certain stand of the five-stand cold continuous rolling mill. The specific technical solution is as follows:

[0010] A) Setting rolling parameters and front and rear stand equipment parameters, which mainly include: set inlet thickness H of the strip steel at the i-1-th stand i-1 ; set outlet thickness h of the strip steel at the i-1-th stand i-1 ; set inlet thickness H of the strip steel at the i-th stand i ; set outlet thickness h of the strip steel at the i-th stand i ; entry rolling speed v0 of the first stand; deformation resistance K of the i-1-th stand i-1 ; front unit tension σ of the i-1-th stand i-1前 ; rear unit tension σ of the i-1-th stand i-1后 ; work roll diameter D of the i-1-th stand i-1 ; friction coefficient μ of the i-1-th stand i-1 ; set rolling force P of the i-1-th stand i-1 ; set rolling force P of the i-th stand i ; deformation resistance K of the i-th stand i ; front unit tension σ of the i-th stand i前 ; rear unit tension σ of the i-th standi后 Incoming material width B; Diameter of the working roller of the i-th frame D i The friction coefficient μ of the i-th frame i Elastic modulus E; Poisson's ratio ν; Rolling power W of the (i-1)th stand i-1 The efficiency η of the motor in the (i-1)th rack i-1 The rolling power W of the i-th stand i The efficiency η of the motor in the i-th rack i .

[0011] B) Check if i > 1. If i > 1, jump to C). If i = 1, let v i-1 =v0 and jump to F).

[0012] C) Calculate the forward slip value f of the (i-1)th frame. i-1s .

[0013]

[0014] In the formula: R' i-1 —The flattening radius of the (i-1)th frame is expressed by the following formula:

[0015]

[0016] D) Calculate the rolling torque M of the (i-1)th stand. i-1 .

[0017]

[0018] In the formula: ξ i-1 —Equivalent tension influence coefficient of the (i-1)th frame, ξ i-1 =0.3σ i-1前 +0.7σ i-1后 ;

[0019] Q i-1G —The influence coefficient of external friction of the (i-1)th frame is expressed by the following formula:

[0020]

[0021] r i-1 —Reduction rate of the i-1th rack pass

[0022] E) Calculate the rolling speed v at the exit of the (i-1)th stand. i-1 .

[0023]

[0024] F) Calculate the forward slip value f of the i-th frame. is .

[0025]

[0026] In the formula: R' i —The flattening radius of the i-th frame is expressed by the following formula:

[0027]

[0028] G) Calculate the rolling torque M of the i-th stand. i .

[0029]

[0030] In the formula: ξ i —Equivalent tension influence coefficient of the i-th frame, ξ i =0.3σ i前 +0.7σ i后 ;

[0031] Q iG —The external friction influence coefficient of the i-th frame is expressed by the following formula:

[0032]

[0033] r i —Reduction rate of the i-th rack pass

[0034] H) Calculate the rolling speed v at the exit of the i-th stand. i .

[0035]

[0036] I) Calculate the thickness deviation rate e at the outlet of the i-th rack.

[0037]

[0038] Compared with the prior art, the advantages of the present invention are as follows: (1) The present invention can fully combine the equipment characteristics of the five-stand cold rolling mill unit according to the on-site production conditions of cold-rolled strip steel, and obtain the inlet and outlet rolling speed of a certain stand by the rolling force setting value under the condition of a certain rolling power. The obtained inlet and outlet rolling speed of the stand is substituted into the established outlet thickness deviation rate model to obtain the predicted value of the outlet thickness deviation rate of a certain stand of the five-stand cold rolling mill unit; (2) The present invention can predict the outlet thickness deviation rate of a certain stand of the five-stand cold rolling mill unit more accurately before production, provide enterprises with rolling parameter adjustment reference, improve the quality of strip steel rolled products, and bring greater economic benefits. Attached Figure Description

[0039] Figure 1 This application presents a flowchart of a method for predicting the thickness deviation rate at the exit of a certain stand in a five-stand cold rolling mill. Detailed Implementation

[0040] Taking the first and second stands of a five-stand cold rolling mill as an example, combined with... Figure 1 This invention provides a detailed description of a method for predicting the thickness deviation rate at the exit of a certain stand in a five-stand cold rolling mill.

[0041] Example 1:

[0042] First, in step A), the rolling parameters and the parameters of the front and rear stands are set, mainly including: the strip thickness setting value H1 at the first stand entrance; the strip thickness setting value h1 at the first stand exit; the rolling speed v0 at the first stand entrance; the rolling force setting value P1 at the first stand; the deformation resistance K1 at the first stand; and the unit tension σ at the front of the first stand. 1前 Unit tension σ behind the first frame 1后 ; Incoming material width B; Diameter of the first stand work roll D1; Friction coefficient of the first stand μ1; Elastic modulus E; Poisson's ratio ν; Rolling power of the first stand W1; Motor efficiency of the first stand η1.

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

[0044] Rolling force setting value / N 8400000 Rolling speed at the entrance of stand 1 (m / min) 150 Strip entry thickness setting value / mm 3 Strip exit thickness setting value / mm 1.8 Deformation resistance / MPa 700 unit tension / MPa 150 Unit tension after 100 Incoming material width / mm 950 Work roll diameter / mm 404 coefficient of friction 0.04 Elastic modulus / MPa 210000 Poisson's ratio 0.3 Rolling power / kW 4400 Motor efficiency / % 80

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

[0046] Subsequently, in step F), the forward slip value f of the first frame is calculated. 1s .

[0047]

[0048] In the formula: R'1—the flattening radius of the first frame, expressed by the following formula:

[0049]

[0050] Calculate f 1s =0.0019.

[0051] Then, in step G), the rolling torque M1 of the first stand is calculated.

[0052]

[0053] In the formula: ξ1—Equivalent tension influence coefficient of the first frame, ξ1=0.3σ 1前 +0.7σ 1后 ;

[0054] Q 1G —The external friction influence coefficient of the first frame is expressed by the following formula:

[0055]

[0056] r1—Reduction rate of the first rack pass

[0057] The calculated value is M1 = 175970.4 N·m.

[0058] Then, in step H), the rolling speed v1 at the exit of the first stand is calculated.

[0059]

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

[0061] Finally, in step I), the thickness deviation rate e at the exit of the first frame is calculated.

[0062]

[0063] Where: r1—reduction rate of the first stand pass,

[0064] The calculated value is e = 2.924%.

[0065] Example 2:

[0066] First, in step A), the rolling parameters and the parameters of the front and rear stands are set, mainly including: the strip thickness setting value H1 at the first stand entrance; the strip thickness setting value h1 at the first stand exit; the rolling speed v0 at the first stand entrance; the rolling force setting value P1 at the first stand; the deformation resistance K1 at the first stand; and the unit tension σ at the front of the first stand. 1前 Unit tension σ behind the first frame 1后 Incoming material width B; 1st stand work roll diameter D1; 1st stand friction coefficient μ1; elastic modulus E; Poisson's ratio ν; 1st stand rolling power W1; 1st stand motor efficiency η1; 2nd stand strip inlet thickness setting H2; 2nd stand strip outlet thickness setting h2; 2nd stand rolling force setting P2; 2nd stand deformation resistance K2; 2nd stand front unit tension σ 2前 The unit tension σ behind the second frame 2后 ; Diameter of the work roll of the second stand D2; Friction coefficient of the second stand μ2; Rolling power of the second stand W2; Motor efficiency of the second stand η2.

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

[0068] Rolling force setting value / N 8400000 8000000 Rolling speed at the entrance of stand 1 (m / min) 150 150 Strip entry thickness setting value / mm 3 1.8 Strip exit thickness setting value / mm 1.8 1 Deformation resistance / MPa 700 760 unit tension / MPa 150 150 Unit tension after 100 100 Incoming material width / mm 950 950 Work roll diameter / mm 404 400 coefficient of friction 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), if i > 1 and i = 2 > 1, then jump to step C).

[0070] Subsequently, in step C), the forward slip value f of the first frame is calculated. 1s .

[0071]

[0072] In the formula: R'1—the flattening radius of the first frame, expressed by the following formula:

[0073]

[0074] Calculate f 1s =0.0019.

[0075] Then, in step D), the rolling torque M1 of the first stand is calculated.

[0076]

[0077] In the formula: ξ1—Equivalent tension influence coefficient of the first frame, ξ1=0.3σ 1前 +0.7σ 1后 ;

[0078] Q 1G —The external friction influence coefficient of the first frame is expressed by the following formula:

[0079]

[0080] r1—Reduction rate of the first rack pass

[0081] The calculated value is M1 = 175970.4 N·m.

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

[0083]

[0084] The calculated speed is v1 = 242.9 m / min.

[0085] Subsequently, in step F), the forward slip value f of the second frame is calculated. 2s .

[0086]

[0087] In the formula: R'2—the flattening radius of the second frame, expressed by the following formula:

[0088]

[0089] Calculate f 2s =0.037.

[0090] Then, in step G), the rolling torque M2 of the second stand is calculated.

[0091]

[0092] In the formula: ξ2—the equivalent tension influence coefficient of the second frame, ξ2=0.3σ 2前 +0.7σ 2后 ;

[0093] Q 2G —The external friction influence coefficient of the second frame is expressed by the following formula:

[0094]

[0095] r2—Reduction rate of the second stand pass

[0096] The calculated value is M² = 135871.3 N·m.

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

[0098]

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

[0100] Finally, in step I), the thickness deviation rate e at the exit of the second frame is calculated.

[0101]

[0102] Where: r2—reduction rate of the second stand pass,

[0103] The calculated value is e = 3.75%.

[0104] It should be noted that the above embodiments are not intended to limit the scope of protection of the present invention. Equivalent transformations or substitutions made based on the above technical solutions all fall within the scope of protection of the claims of the present invention.

Claims

1. A method for predicting the thickness deviation rate at the exit of a certain stand in a five-stand cold rolling mill, characterized in that, The method includes the following steps: A) Set the rolling parameters and the parameters for the front and rear stands. B) Check if i > 1. If i > 1, jump to C). If i = 1, let... And jump to F). C) Calculate the forward slip value of the (i-1)th frame. , D) Calculate the rolling torque of the (i-1)th stand. , E) Calculate the exit rolling speed of the (i-1)th stand. , F) Calculate the forward slip value of the i-th frame. , G) Calculate the rolling torque of the i-th stand. , H) Calculate the exit rolling speed of the i-th stand. , I) Calculate the out-of-tolerance rate of the exit thickness of the i-th frame. ; Among them, A) setting the rolling parameters and the parameters of the front and rear stands mainly includes: the setting value of the strip entry thickness of the (i-1)th stand. ; Strip exit thickness setting value for the (i-1)th frame ; Strip entry thickness setting value for the i-th frame ; Strip exit thickness setting value for the i-th frame Rolling speed at the entrance of stand 1 Deformation resistance of the (i-1)th frame Unit tension at the front of frame i-1 Unit tension after frame i-1 Diameter of the working roll of the (i-1)th frame ; coefficient of friction of the (i-1)th frame ; Rolling force setting value for the (i-1)th stand ; Rolling force setting value of the i-th stand Deformation resistance of the i-th frame ; Unit tension at the front of the i-th frame Unit tension after the i-th frame Incoming material width Diameter of the working roll of the i-th frame ; coefficient of friction of the i-th frame Elastic modulus Poisson's ratio Rolling power of the (i-1)th stand ; Efficiency of the motor in the (i-1)th rack ; Rolling power of the i-th stand ; Efficiency of the motor in the i-th rack ; E) Calculate the exit rolling speed of the (i-1)th stand. , ； H) Calculate the exit rolling speed of the i-th stand. , ， I) Calculate the out-of-tolerance rate of the exit thickness of the i-th frame. , ,in, Let be the reduction rate of the i-th rack pass.

2. The method for predicting the thickness deviation rate at the exit of a certain stand in a five-stand cold rolling mill according to claim 1, characterized in that, C) Calculate the forward slip value of the (i-1)th frame. , In the formula: —The flattening radius of the (i-1)th frame is expressed by the following formula: 。 3. The method for predicting the thickness deviation rate at the exit of a certain stand in a five-stand cold rolling mill according to claim 1, characterized in that, D) Calculate the rolling torque of the (i-1)th stand. , In the formula: —Equivalent tension influence coefficient of the (i-1)th frame ; —The influence coefficient of external friction of the (i-1)th frame is expressed by the following formula: ； —Reduction rate of the i-1th rack pass .

4. The method for predicting the thickness deviation rate at the exit of a certain stand in a five-stand cold rolling mill according to claim 1, characterized in that, F) Calculate the forward slip value of the i-th frame. , In the formula: —The flattening radius of the i-th frame is expressed by the following formula: 。 5. The method for predicting the thickness deviation rate at the exit of a certain stand in a five-stand cold rolling mill according to claim 1, characterized in that, G) Calculate the rolling torque of the i-th stand. , In the formula: —Equivalent tension influence coefficient of the i-th frame ; —The coefficient of influence of external friction on the i-th frame is expressed by the following formula: ； —Reduction rate of the i-th rack pass .

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