A method for predicting the tower shape of steel coils during the coiling process of a pickling mill

Abstract

The present invention relates to a method for predicting the amount of steel coil spire during the coiling process of a pickling mill, comprising the steps of collecting process parameters, calculating the amount of spire caused by deviation, and calculating the amount of steel coil spire caused by coil deflection. The method provides a method for predicting the amount of steel coil spire during the coiling process of a pickling mill. By collecting on-site rolling and coiling process parameters, the method predicts the amount of strip spire at the pinch rolls and the amount of coil deflection during the coiling process, thereby predicting the amount of finished steel coil spire. This method can provide guidance for on-site production and lay a good foundation for subsequent control of spire.

Description

Technical Field

[0001] The invention relates to a method for predicting the tower shape of a steel coil in a coiling process of a pickling mill, and belongs to the technical field of metallurgy. Background Art

[0002] With the continuous development of my country's manufacturing industry, the role of the cold-rolled sheet and strip industry is growing. Coiling, as the process closest to the finished product, plays a crucial role in ensuring high-quality storage and transportation of steel coils. Due to process and equipment limitations, towering defects often occur during the coiling process. Towering defects not only affect coil quality and yield, but can also easily damage the coil edges during transportation and lifting, increasing repair costs and resulting in significant economic losses for the unit.

[0003] After long-term on-site tracking by the inventors, it was found that during the coiling process, the pinch roller and the steering roller were not installed accurately or were worn out, resulting in the axis between the two being not level, causing the strip to deviate during the coiling process, thus causing the steel coil to form a tower shape; there was also the deflection of the reel caused by the weight of the steel coil itself, which made the axis of the reel not level, also causing the steel coil to form a tower shape.

[0004] In the prior art, there is no technical solution for predicting the tower volume of the steel coil to be produced by using the coiling process parameters during the production process, which cannot effectively avoid the economic benefit loss caused by the tower volume on site. Summary of the Invention

[0005] The technical problem to be solved by the present invention is: to overcome the shortcomings of the above-mentioned technology and provide a method that combines production equipment and on-site production practices to predict the towering amount caused by strip deviation and reel deflection, and finally predict the towering amount of steel coil during the coiling process.

[0006] In order to solve the above technical problems, the present invention proposes a technical solution: a method for predicting the tower shape of steel coils in the coiling process of a pickling mill, comprising the following steps:

[0007] Step 1: Collect on-site equipment process parameters; measure the distance L1 between the pinch roller and the steering roller, the angle α between the pinch roller and the steering roller axis, the tangent distance L2 between the steering roller and the coil being wound, the coil bending strength K1, the bracket bending strength K2, the strip width B, the strip thickness h, the coil radius r, the strip mass per unit volume m, the number of winding layers n, one end of the coil is connected to the large turntable as the fixed end, and the other end is supported by the bracket as the free end; when the steel coil is on the coil, the coil can be divided into three sections in the length direction, that is, the distance l1 from the end face of the steel coil facing the fixed end to the fixed end, the width l2 of the steel coil itself, and the distance l3 from the other end face of the steel coil to the free end.

[0008] Step 2: Define the pyramid correction coefficients λ1 and λ2; where the value range of λ1 is 0.09 to 0.11, and the value range of λ2 is 9 to 11;

[0009] Step 3: Calculate the strip deviation δ = λ1L1 sinα caused by the angle between the pinch roller and the steering roller axis; calculate the pyramidal amount Δ1 = nδ caused by the deviation;

[0010] Step 4: Calculate the uniform load q on the drum n =mgh[nπR+πhn(n+1) / 2]; calculate the support reaction force F at the fixed end of the large turntable Dy =q n l2-F, and calculate the torque at the fixed end of the large turntable Where F is the support force of the bracket at the free end of the large turntable on the drum;

[0011] Step 5: The three bending moment equations of the segment are as follows:

[0012] When 0≤x≤l1,

[0013] When l1≤x≤l1+l2,

[0014] When l1+l2≤x≤l1+l2+l3,

[0015]

[0016] Step 6: Calculate according to the deflection curve formula Kω″=M in material mechanics, where K is the bending strength and ω is the deflection curve;

[0017] Let K = K1, and substitute M1, M2, and M3 of the above bending moment equation into M respectively, and perform two integrations respectively, adding a constant term each time; according to the boundary conditions, there is ω at the fixed end of the large turntable x＝0 =0,ω′ x＝0 = 0, solve for the two constant terms in K1ω′=∫M1 and K1ω=∫∫M1; substitute x=l1 into K1ω′=∫M1, K1ω=∫∫M1, and solve and According to the continuity of the deflection curve, at x = l1, ω and ω′ in the previous and next equations are equal, and the solution is and Substitute the numerical value into K1ω′=∫M2 and K1ω=∫∫M2 to solve the two constant terms of the two integrals of K1ω″=M2, and solve The numerical value of x=l1+l2, ω and ω′ in the equation before and after are equal, and the solution is Substitute the value of into K1ω′=∫M3 and K1ω=∫∫M3 to solve the two constant terms of the two integrals of K1ω″=M3; now all 6 constant terms have been solved;

[0018] Step 7: Substitute x = l1 + l2 + l3 into K1ω = ∫∫M3 to solve the deflection of the free end of the drum. There is only one unknown quantity F. According to the same deflection of the bracket and the drum at the movable end of the large turntable, use Combined with the deflection value obtained in step 6, we can solve for F.

[0019] Step 8: Using F solved in step 7, substitute x = l1 + l2 + l3 into K1ω′ = ∫M3 to calculate the value of ω′ at x = l1 + l2 + l3. Use Δ2 = λ2L2 sinω′ to calculate the amount of towering of the steel coil caused by the deflection of the drum.

[0020] Step 9: Obtain the tower shape of the steel coil Δ=Δ1+Δ2.

[0021] The method for predicting coil sag during the coiling process of a pickling mill, provided by this invention, collects on-site rolling and coiling process parameters to predict the strip deviation at the pinch rolls and the deflection of the coil during the coiling process, thereby predicting the sag of the finished coil. This can provide guidance for on-site production and lay a good foundation for subsequent sag control. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the winding process in the embodiment.

[0023] Figure 2 2 is a force analysis diagram of the reel in the embodiment. DETAILED DESCRIPTION

[0024] Example 1

[0025] The method for predicting the tower shape of steel coils in the coiling process of the pickling mill in this embodiment takes a pickling mill as an example and combines Figure 1 and Figure 2 , for detailed explanation.

[0026] A) Collect on-site equipment process parameters, including the distance between the pinch roller and the steering roller (L1 = 2775 mm), the angle between the pinch roller and the steering roller axis (α = 0.0029°), the tangent distance between the steering roller and the coiled steel coil (L2 = 3688 mm), the coil bending strength (K1 = 1000 MPa), the bracket bending strength (K2 = 400 MPa), the strip width (B) = 898 mm, the strip thickness (h) = 0.2 mm, the coil radius (R) = 508 mm, the strip mass per unit volume (m) = 7850 kg, the number of coiling layers (n) = 2000, and the coiling process diagram as shown in the figure. Figure 1 As shown;

[0027] B) Define tower shape correction coefficients λ1 and λ2. The tower shape correction coefficients are obtained by regression based on actual production conditions. For this unit, the tower shape correction coefficients are λ1 = 0.1 and λ2 = 10.

[0028] C) Calculate the strip deviation caused by the angle between the pinch roller and the steering roller axis δ = λ1L1 sinα, and then calculate the pyramidal amount caused by the deviation Δ1 = nδ = 0.1 × 2775 × sin0.0029 × 2000 ≈ 28 mm;

[0029] D) If Figure 2 As shown, calculate the uniform load q on the drum n =mgh[nπr+πhn(n+1) / 2]=69KN / m; solve for the support reaction force at the D end of the large turntable, and use F to represent the support force of the bracket on the drum at the free end C.

[0030] E) First express the bending moment equation in sections, such as Figure 2 As shown, it is divided into 0≤x≤l1, l1≤x≤l1+l2, l1+l2≤x≤l1+l2+l3, and the bending moment equations are:

[0031]

[0032]

[0033]

[0034] F) Calculate the deflection curve according to the formula Kω″=M, where ω represents the deflection curve and M is the bending moment equation mentioned above;

[0035] G) For the convenience of description, Kω″=M is denoted as f″(ω), and the three bending moment equations are substituted into them respectively. Then, the three equations are integrated twice. Six more constant terms are obtained by integrating the three equations twice. According to the boundary conditions, ω=0 and ω′=0 at the D end, so the two constant terms f1′(ω) and f1(ω) can be solved. According to the continuity of the deflection, when x=l1, f1′(ω)=f2′(ω) and f1(ω)=f2(ω), so the two constant terms f2′(ω) and f2(ω) can be solved. Similarly, all six constant terms have been solved.

[0036] H) Based on the fact that the deflection of the bracket and the drum at the C end is the same, use ω c =F / K2 to replace the bracket support force F in f2′(ω) and f2(ω); take l1=470mm, l2=898mm, l3=800mm to calculate F=200KN;

[0037] I) Substituting x = l1 + l2 + l3 into f3′(ω), we calculated ω′ = 0.0089°. Using Δ2 = λ2L2 sinω′, we calculated the amount of towering steel coil caused by the deflection of the coil drum. The on-site measurement of L2 = 3688 mm resulted in a calculated Δ2 = 5.7 mm.

[0038] J) Combining the formula in step C, the calculation model for the tower shape of the steel coil is Δ = Δ1 + Δ2 = 33.7 mm.

[0039] Example 2

[0040] A) Collect on-site equipment process parameters, including the distance between the pinch roller and the steering roller (L1 = 2775 mm), the angle between the pinch roller and the steering roller axis (α = 0.003°), the tangent distance between the steering roller and the coiled steel coil (L2 = 3688 mm), the coil bending strength (K1 = 1000 MPa), the bracket bending strength (K2 = 400 MPa), the strip width (B) = 1003 mm, the strip thickness (h) = 0.48 mm, the coil radius (R) = 508 mm, the strip mass per unit volume (m) = 7850 kg, the number of coiling layers (n) = 2000, and the coiling process diagram as shown below. Figure 1 As shown;

[0041] B) Define tower shape correction coefficients λ1 and λ2. The tower shape correction coefficients are obtained by regression based on actual production conditions. For this unit, the tower shape correction coefficients are λ1 = 0.1 and λ2 = 10.

[0042] C) Calculate the strip deviation caused by the angle between the pinch roller and the steering roller axis δ = λ1L1 sinα, and then calculate the pyramidal amount caused by the deviation Δ1 = nδ = 0.1 × 2775 × sin0.003 × 2000 ≈ 29 mm;

[0043] D) If Figure 2 As shown, calculate the uniform load q on the drum n =mgh[nπr+πhn(n+1) / 2]=69KN / m; solve for the support reaction force at the D end of the large turntable, and use F to represent the support force of the bracket on the drum at the free end C.

[0044] E) First express the bending moment equation in sections, such as Figure 2 As shown, it is divided into 0≤x≤l1, l1≤x≤l1+l2, l1+l2≤x≤l1+l2+l3, and the bending moment equations are:

[0045]

[0046]

[0047]

[0048] F) Calculate the deflection curve according to the formula Kω″=M, where ω represents the deflection curve and M is the bending moment equation mentioned above;

[0049] G) For the convenience of description, Kω″=M is denoted as f″(ω), and the three bending moment equations are substituted into them respectively. Then, the three equations are integrated twice. Six more constant terms are obtained by integrating the three equations twice. According to the boundary conditions, ω=0 and ω′=0 at the D end, so the two constant terms f1′(ω) and f1(ω) can be solved. According to the continuity of the deflection, when x=l1, f1′(ω)=f2′(ω) and f1(ω)=f2(ω), so the two constant terms f2′(ω) and f2(ω) can be solved. Similarly, all six constant terms have been solved.

[0050] H) Based on the fact that the deflection of the bracket and the drum at the C end is the same, use ω c =F / K2 to replace the bracket support force F in f2′(ω) and f2(ω); taking l1=417.5mm, l2=1003mm, l3=747.5mm, we can calculate F=223KN:

[0051] I) Substituting x = l1 + l2 + l3 into f3′(ω), we calculate ω′ = 0.0099°. Calculate the amount of convolution of the coil due to drum deflection using Δ2 = λ2L2 sinω′, and calculate Δ2 = 6.4 mm.

[0052] J) Combining the formula in step C, the calculation model for the tower shape of the steel coil is Δ = Δ1 + Δ2 = 35.4 mm.

[0053] The present invention is not limited to the above embodiments. Any technical solutions formed by equivalent replacement fall within the protection scope required by the present invention.

Claims

1. A method for predicting the tower shape of steel coils in the coiling process of a pickling mill, characterized in that: The steps include: Step 1: Collect on-site equipment process parameters; measure the distance L1 between the pinch roller and the steering roller, the angle α between the pinch roller and the steering roller axis, the tangent distance L2 between the steering roller and the coil being wound, the coil bending strength K1, the bracket bending strength K2, the strip width B, the strip thickness h, the coil radius r, the strip mass per unit volume m, the number of coiling layers n, and one end of the coil connected to the large turntable as the fixed end, while the other end is supported by the bracket as the free end; When the steel coil is on the reel, the reel can be divided into three sections in the length direction, namely, the distance l1 from the end face of the steel coil facing the fixed end to the fixed end, the width of the steel coil itself l2, and the distance l3 from the other end face of the steel coil to the free end. Step 2: Define the pyramid correction coefficients λ1 and λ2; where the value range of λ1 is 0.09 to 0.11, and the value range of λ2 is 9 to 11; Step 3: Calculate the strip deviation δ = λ1L1sinα caused by the angle between the pinch roller and the steering roller axis; calculate the pyramidal amount Δ1 = nδ caused by the deviation; Step 4: Calculate the uniform load q on the drum n =mgh[nπr+πhn(n+1) / 2]; calculate the support reaction force F at the fixed end of the large turntable Dy =q n l2-F, and calculate the torque at the fixed end of the large turntable Where F is the support force of the bracket at the free end of the large turntable on the drum; Step 5: The three bending moment equations of the segment are as follows: When 0≤x≤l1, When l1≤x≤l1+l2, <h2 style=";text-align:left;direction:ltr">l1+l2≤x≤l1+l2+l3,<h2 style=";text-align:left;direction:ltr"> Step 6: Calculate according to the deflection curve formula Kω″=M in material mechanics, where K is the bending strength and ω is the deflection curve; Let K = K1, and substitute M1, M2, and M3 of the above bending moment equation into M respectively, and perform two integrations respectively, adding a constant term each time; according to the boundary conditions, there is ω at the fixed end of the large turntable x＝0 =0,ω′ x＝0 = 0, solve for the two constant terms in K1ω′=∫M1 and K1ω=∫∫M1; substitute x=l1 into K1ω′=∫M1, K1ω=∫∫M1, and solve and According to the continuity of the deflection curve, at x = l1, ω and ω′ in the previous and next equations are equal, and the solution is and Substitute the numerical value into K1ω′=∫M2 and K1ω=∫∫M2 to solve the two constant terms of the two integrals of K1ω″=M2, and solve The numerical value of x=l1+l2, ω and ω′ in the equation before and after are equal, and the solution is Substitute the value of into K1ω′=∫M3 and K1ω=∫∫M3 to solve the two constant terms of the two integrals of K1ω″=M3; now all 6 constant terms have been solved; Step 7: Substitute x = l1 + l2 + l3 into K1ω = ∫∫M3 to solve the deflection of the free end of the drum. There is only one unknown quantity F. According to the same deflection of the bracket and the drum at the movable end of the large turntable, use Combined with the deflection value obtained in step 6, we can solve for F. Step 8: Using F solved in step 7, substitute x = l1 + l2 + l3 into K1ω′ = ∫M3 to calculate the value of ω′ at x = l1 + l2 + l3. Use Δ2 = λ2L2sinω′ to calculate the amount of towering of the steel coil caused by the deflection of the drum. Step 9: Obtain the tower shape of the steel coil Δ=Δ1+Δ2.

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