Rolling mill roll gap leveling and pre-swinging method based on head shape of plate blank before rolling

Abstract

The invention relates to the technical field of rough rolling of hot continuous rolling, in particular to a rolling mill roll gap leveling pre-swing method based on the head shape of a plate blank before rolling, which is used for calculating a rolling mill roll gap leveling value before strip steel enters a rolling mill and comprises the following steps: arranging a side guide plate and a plate blank center line measuring device at a rolling inlet of the rolling mill; according to the head bending detection value of the incoming plate blank and the side guide plate parameters, the position of the plate blank deviating from the rolling center line when entering the rolling mill is calculated, and the rolling mill roll gap leveling value is calculated according to the rolling process parameters. The method has the advantages that the position, deviating from the rolling center line, of the plate blank when the plate blank enters the rolling mill is calculated according to the head bending detection value of the supplied plate blank and the side guide plate parameters, then the roll gap leveling value of the rolling mill is calculated according to the rolling process parameters, and therefore the stability of the rolling process and the product plate shape control precision are improved, and the plate shape quality of the plate blank is improved; the rolling mill roll gap leveling pre-swing value of the head shape of the plate blank before rolling is automatically given, generation of plate blank camber and intervention of operators are reduced, and labor intensity is lowered.

Description

Technical Field

[0001] The present invention relates to the technical field of hot continuous rolling rough rolling, and particularly relates to a method for pre-swinging and leveling the roll gap of a rolling mill based on the shape of the head of a slab before rolling. Background Art

[0002] The iron and steel industry is one of the important components of modern industry. As an important raw material for many industries in the national economy, strip steel accounts for nearly 40% of the total steel consumption. With the rapid development of industries such as ship port machinery, bridge construction, aerospace, and automotive household appliances, the demand for strip steel has increased sharply. However, during the strip steel rolling process, due to the influence of asymmetric shape factors, asymmetric shape defects will occur. In hot rolling rough rolling, the problem of camber will occur, which not only affects the shape quality of the product, reduces the service life of equipment, but also may affect production stability and even cause potential safety hazards. According to statistics, during the rolling production process, the scrap steel caused by asymmetric shape defects every year accounts for about 30% - 50% of the total scrap steel volume, resulting in serious waste of resources and economic losses, which is a worldwide problem that has attracted extensive attention from production enterprises and research fields.

[0003] During the rough rolling process of slabs, the slabs will bend. Therefore, during each rough rolling pass, it is necessary to adjust the camber of the slabs by tilting the roll gap of the rolling mill. When the bent slabs enter the next rolling pass, since the position where they enter the rolling mill deviates from the rolling center line, it is necessary to accurately calculate the roll gap leveling value for adjustment to avoid generating a larger camber. Although side guide plates are usually arranged at the entrance of the rolling mill for slab centering, for slabs with a bent head, the side guide plate centering only changes the overall position of the slab. It is still necessary to accurately calculate the center position of the strip steel entering the rolling mill in order to calculate the roll gap leveling value in combination with the roll-rolled piece deformation and timely adjust the camber to ensure the smooth progress of rolling and improve the shape quality of the slabs.

[0004] In the prior art, the patent application No. 200710036563.6 discloses "a method for controlling the camber of an intermediate billet in rough rolling", which jointly controls the position and pressure of the side guide plate. The position control of the side guide plate refers to the short-stroke control of the side guide plate, that is, when the intermediate billet has not entered the side guide plate, the opening of the side guide plate is in the waiting position, and the size of the opening is equal to the width of the intermediate billet plus the first additional value. At this time, the opening of the side guide plate is much larger than the width of the intermediate billet; when the intermediate billet enters a certain position within the side guide plate area, the opening of the side guide plate is reduced to the width of the intermediate billet plus the second additional value, and the second additional value is adjusted according to the actual situation; after the short-stroke action ends, the opening of the side guide plate remains constant; the pressure control of the side guide plate is to control the side guide plate to be in the state of the set pressing force through a servo valve. When the actual pressing force is greater than the set pressure, the opening of the side guide plate is appropriately opened, and vice versa, appropriately closed, so that the side guide plate is always in contact with the intermediate billet, and the bending of the intermediate billet in the horizontal direction is restricted; by combining position control and pressure control, in the multi-pass rolling of the rough rolling mill in the forward and reverse passes, the generation of camber of the intermediate billet is suppressed; this invention uses the side guide plate to clamp the slab through pressure to improve the shape of the rough rolling camber, but does not consider the impact of the existing camber on rolling. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for pre-setting and leveling the roll gap of a rolling mill based on the shape of the head of the slab before rolling, to improve the stability of the rolling process and the accuracy of product shape control, to improve the shape quality of the slab, to reduce the generation of slab camber and the intervention of operators, and to reduce the labor intensity.

[0006] To achieve the above purpose, the present invention is realized through the following technical solutions:

[0007] A method for pre-setting and leveling the roll gap of a rolling mill based on the shape of the head of the slab before rolling. During hot rolling, calculate the roll gap leveling value of the rolling mill before the strip steel enters the rolling mill, including:

[0008] S1. Install a side guide plate and a slab centerline measuring device at the rolling mill entrance.

[0009] S2. According to the detected value of the head bending of the incoming slab and the side guide plate parameters, calculate the position where the slab deviates from the rolling centerline when it enters the rolling mill, and calculate the roll gap leveling value of the rolling mill according to the rolling process parameters.

[0010] In S1, the slab centerline measuring device uses an industrial camera.

[0011] In S2, calculate the position where the slab deviates from the rolling centerline when it enters the rolling mill. The formula is as follows:

[0012]

[0013] In formula ①, ΔZ represents the offset of the center point of the head of the slab to be rolled from the rolling center line, x0 represents the first measurement data of the head of the slab obtained by the industrial camera before the slab to be rolled enters the rolling mill, and x n represents the (n + 1)-th measurement data of the head of the slab obtained by the industrial camera before the slab to be rolled enters the rolling mill, and x 2n represents the (2n + 1)-th measurement data of the head of the slab obtained by the industrial camera before the slab to be rolled enters the rolling mill (n = 1 / 2[l / tv]), v represents the running speed of the slab, t represents the time interval between two adjacent data points of the shooting device, l is the length of the entrance side guide plate, and x 2n being a positive value indicates that the slab to be rolled is biased towards the drive side of rolling.

[0014] In S2, calculate the roll gap leveling value of the rolling mill, and the formula is as follows:

[0015]

[0016] In formula ②, ΔS represents the calculated value of roll gap leveling for the current pass, ΔZ represents the offset of the center point of the head of the slab to be rolled from the rolling center line, α is the strip width influence coefficient, K DS represents the stiffness of the drive side, K OS represents the stiffness of the operating side, P represents the predicted rolling force for the current pass, and L represents the distance between the centers of the hydraulic cylinders on both sides of the rolling mill.

[0017] Confirm the offset of the center point of the head of the slab to be rolled from the rolling center line, and the steps are as follows:

[0018] S31. Obtain the continuous measurement data of the center line of the entrance slab, and the formula is as follows:

[0019] {x0, x1, …, x 2n}③

[0020] In formula ③, x0 represents the first measurement data of the head of the slab obtained by the industrial camera before the slab to be rolled enters the rolling mill, x1 represents the second measurement data of the head of the slab obtained by the industrial camera before the slab to be rolled enters the rolling mill, and x 2n represents the (2n + 1)-th measurement data of the head of the slab obtained by the industrial camera before the slab to be rolled enters the rolling mill, and x 2n being a positive value indicates that the slab to be rolled is biased towards the drive side of rolling;

[0021] S32. Calculate the offset ΔZ of the center point of the head of the slab to be rolled from the rolling center line.

[0022] Calculate the strip width influence coefficient, and the formula is as follows:

[0023]

[0024] In formula ④, L RLet \(L\) represent the length of the roll surface, \(B\) represent the width of the rolled strip, and \(G\) represent the strip lateral flow factor. The strip lateral flow factor \(G\) is related to the slab steel grade, width, and thickness. The strip lateral flow factor \(G\) is obtained by establishing a proportional rolling mill workpiece model using a commercial finite element model and is calculated through simulation. The value range is \([0, 0.2]\).

[0025] The stiffness of the drive side and the operating side is obtained through the stiffness test of the rolling mill. During the stiffness test, the rolling mill adopts step-by-step reduction - pressure holding - reduction treatment, and the unloading process also adopts step-by-step reduction - pressure holding - reduction treatment. The reduction force needs to exceed 18,000 kN.

[0026] In S2, the side guide plate parameters include the side guide plate length.

[0027] In S2, the rolling process parameters include the calculated value of the roll gap leveling for the current pass, the offset of the center point of the head of the slab to be rolled from the rolling center line, the predicted rolling force for the current pass, the distance between the center points of the hydraulic cylinders on both sides of the rolling mill, the stiffness of the drive side, the stiffness of the operating side, the strip width influence coefficient, the width of the rolled strip, the length of the roll surface, and the strip lateral flow factor.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] 1. According to the bending detection value of the head of the incoming slab and the side guide plate parameters, calculate the position where the slab deviates from the rolling center line when entering the rolling mill, and then calculate the roll gap leveling value of the rolling mill according to the rolling process parameters, thereby improving the stability of the rolling process and the accuracy of product shape control, and improving the shape quality of the slab.

[0030] 2. Automatically give the pre-swing value of the roll gap leveling for the shape of the head of the slab before rolling, reduce the generation of slab camber and the intervention of operators, and reduce the labor intensity. Brief Description of the Drawings

[0031] Figure 1 It is a schematic diagram of the reduction inclination during the strip rolling process. Detailed Embodiments

[0032] The present invention will be described in detail below with reference to the drawings of the specification, but it should be noted that the implementation of the present invention is not limited to the following embodiments.

[0033] The following embodiments are implemented on the premise of the technical solution of the present invention, and detailed implementation manners and specific operation processes are given, but the protection scope of the present invention is not limited to the following embodiments. The methods used in the following embodiments are all conventional methods unless otherwise specified.

[0034] Embodiment 1

[0035] Take the last pass of the R2 roughing mill on the 1580 production line of a certain factory as an example.

[0036] The method for pre-setting the mill roll gap leveling based on the shape of the head of the slab before rolling is applicable to calculating the tilt leveling value of the mill roll gap before the strip steel enters the rolling mill during the hot rolling process of strip steel, and specifically includes the following content:

[0037] 1. Considering the bending shape of the head of the strip before rolling, side guides are arranged at the rolling entrance of the rolling mill for slab centering, and a slab centerline measuring device is arranged at the rolling entrance of the rolling mill. The slab centerline measuring device uses a laser scanning sensor.

[0038] 2. According to the bending detection value of the head of the incoming slab and the side guide parameters, calculate the position where the slab deviates from the rolling centerline when it enters the rolling mill, and then calculate the mill roll gap leveling value according to the rolling process parameters, as follows:

[0039] Calculate the position where the slab deviates from the rolling centerline when it enters the rolling mill. The formula is as follows:

[0040]

[0041] In formula ①, x0 represents the first measurement data of the head of the slab obtained by the industrial camera before the slab to be rolled enters the rolling mill (the first detection data refers to the data for calculating the position where the slab to be rolled deviates from the rolling centerline before entering the rolling mill), and the value is 32.18 mm; x n represents the (n + 1)-th measurement data of the head of the slab obtained by the industrial camera before the slab to be rolled enters the rolling mill, and the value is -8.96 mm; x 2n represents the (2n + 1)-th measurement data of the head of the slab obtained by the industrial camera before the slab to be rolled enters the rolling mill (n = 1 / 2[l / tv]), and the value is 0 mm; v represents the running speed of the slab, and the value is 2.5 m / s; t represents the interval time between two adjacent data points of the shooting device, and the value is 50 ms; l is the length of the inlet side guide, and the value is 8000 mm; x 2n is a positive value, indicating that the slab to be rolled is biased towards the driving side of rolling; ΔZ represents the offset of the center point of the head of the slab to be rolled from the rolling centerline, and the calculated value is 25.05 mm.

[0042] Calculate the mill roll gap leveling value. The formula is as follows:

[0043]

[0044] In formula ②,

[0045] P represents the predicted rolling force of the current pass, and P = 8526.02 kN is obtained through the on-site L2 system;

[0046] L represents the center distance between the hydraulic cylinders on both sides of the rolling mill, and L = 3000 mm is obtained through the on-site measurement;

[0047] K DSDenote the stiffness on the drive side as K DS = 2472.36 kN / mm;

[0048] K OS Denote the stiffness on the operating side as K OS = 2495.05 kN / mm;

[0049] α represents the influence coefficient of strip width, which is calculated in step 5, and α = 1.38;

[0050] ΔZ represents the offset of the center point of the head of the slab to be rolled from the rolling center line, which is calculated in step 4 to be 25.05 mm;

[0051] From this, ΔS is calculated to be 0.10 mm.

[0052] 3. The offset of the center point of the head of the slab to be rolled from the rolling center line is confirmed according to the following steps:

[0053] S1: Obtain the continuous measurement data of the center line of the incoming slab. The formula is as follows:

[0054] {x0, x1, …, x 2n}③

[0055] In formula ③, x0 represents the first measurement data of the head of the slab obtained by the industrial camera before the slab to be rolled enters the rolling mill, x1 represents the second measurement data of the head of the slab obtained by the industrial camera before the slab to be rolled enters the rolling mill, x 2n represents the (2n + 1)-th measurement data of the head of the slab obtained by the industrial camera before the slab to be rolled enters the rolling mill. x 2n being a positive value indicates that the slab to be rolled is biased towards the drive side of rolling;

[0056] S2: Calculate the offset of the center point of the head of the slab to be rolled from the rolling center line. Calculate the offset of the center point of the head of the slab to be rolled from the rolling center line according to formula ①. Calculate ΔZ to be 25.05 mm based on the calculation result of S1 and the detection result of the center line measurement device arranged at the rolling mill inlet for the slab.

[0057] 4. The influence coefficient of strip width, the formula is as follows:

[0058]

[0059] In formula ④, L R represents the roll surface length, B represents the width of the rolled strip, G represents the strip transverse flow factor. The strip transverse flow factor G is related to the slab steel grade, width and thickness. The strip transverse flow factor G is established by using a commercial finite element model to build a scaled rolling mill rolling piece model and is obtained through simulation calculation. The value range is [0, 0.2], and α = 1.38 is calculated.

[0060] 5. The stiffness K on the drive sideDS For the stiffness K on the operating side OS It is obtained from the stiffness test carried out by the rolling mill. During the stiffness test, the rolling mill adopts step-by-step reduction - pressure holding - reduction treatment, and the unloading process also adopts step-by-step reduction - pressure holding - reduction treatment. The reduction force needs to exceed 18000 kN.

[0061] See Figure 1 , which is a schematic diagram of the reduction tilt during the strip rolling process. In the figure, ΔZ is the offset of the center point of the head of the slab before rolling from the rolling center line, K DS represents the stiffness on the drive side, K OS represents the stiffness on the operating side, L represents the distance between the centers of the hydraulic cylinders on both sides of the rolling mill, and B is the width of the rolled strip.

[0062] The present invention calculates the position where the slab deviates from the rolling center line when entering the rolling mill according to the detected value of the head bending of the incoming slab and the side guide parameters, and then calculates the roll gap leveling value of the rolling mill according to the rolling process parameters, thereby improving the stability of the rolling process and the accuracy of product shape control, and improving the shape quality of the slab; automatically gives the pre-swing value of the roll gap leveling for the shape of the head of the slab before rolling, reduces the generation of slab camber and the intervention of the operator, and reduces the labor intensity.

Claims

1. A method for pre-setting the roll gap leveling based on the shape of the head of the slab before rolling, characterized in that During the hot rolling process, calculating the roll gap leveling value of the strip before entering the rolling mill, including: S1. Install side guide plates and a slab centerline measuring device at the rolling entrance of the rolling mill; S2. Calculate the position where the slab deviates from the rolling centerline when entering the rolling mill according to the head bending detection value of the incoming slab and the side guide plate parameters, and calculate the roll gap leveling value of the rolling mill according to the rolling process parameters.

2. A roll gap leveling pre-setting method based on the shape of the head of the slab before rolling according to claim 1, characterized in that In S1, the slab centerline measuring device uses an industrial camera.

3. A method for pre-setting the roll gap leveling based on the shape of the head of the slab before rolling according to claim 1, characterized in that, In S2, the formula for calculating the position where the slab deviates from the rolling centerline when entering the rolling mill is as follows: In formula ①, ΔZ represents the offset of the center point of the head of the slab to be rolled from the rolling center line, x0 represents the first measurement data of the head of the slab obtained by the industrial camera before the slab to be rolled enters the rolling mill, and x n represents the (n + 1)-th measurement data of the head of the slab obtained by the industrial camera before the slab to be rolled enters the rolling mill, and x 2n represents the (2n + 1)-th measurement data of the head of the slab obtained by the industrial camera before the slab to be rolled enters the rolling mill (n = 1 / 2[l / tv]), v represents the running speed of the slab, t represents the time interval between two adjacent data points of the shooting device, l represents the length of the entrance side guide plate, and x 2n is a positive value, indicating that the slab to be rolled is biased towards the driving side of rolling.

4. A method for pre-setting the leveling of the roll gap of a rolling mill based on the shape of the head of the slab before rolling according to claim 1, characterized in that In S2, the formula for calculating the roll gap leveling value of the rolling mill is as follows: In formula ②, ΔS represents the calculated value of roll gap leveling for the current pass, ΔZ represents the offset of the center point of the head of the slab to be rolled from the rolling center line, α is the influence coefficient of strip width, K DS represents the stiffness on the drive side, K OS represents the stiffness on the operating side, P represents the predicted rolling force for the current pass, and L represents the distance between the centers of the hydraulic cylinders on both sides of the rolling mill.

5. A method for pre-setting the roll gap leveling based on the shape of the head of the slab before rolling according to claim 4, characterized in that, To confirm the offset of the center point of the head of the slab to be rolled from the rolling centerline, the steps are as follows: S31. Obtain the continuous measurement data of the entrance slab centerline, and the formula is as follows: {x0, x1, …, x 2n} ③ In formula ③, x0 represents the first measurement data of the head of the slab obtained by the industrial camera before the slab to be rolled enters the rolling mill, x1 represents the second measurement data of the head of the slab obtained by the industrial camera before the slab to be rolled enters the rolling mill, x 2n represents the (2n + 1)-th measurement data of the head of the slab obtained by the industrial camera before the slab to be rolled enters the rolling mill, x 2n is a positive value, indicating that the slab to be rolled is biased towards the rolling drive side; S32. Calculate the offset ΔZ of the center point of the head of the slab to be rolled from the rolling centerline.

6. A method for pre-setting the roll gap leveling based on the shape of the head of the slab before rolling according to claim 4, characterized in that, Calculate the strip width influence coefficient, and the formula is as follows: In formula ④, L R represents the length of the roll surface, B represents the width of the rolled strip, G represents the strip lateral flow factor. The strip lateral flow factor G is related to the slab steel grade, width and thickness. The strip lateral flow factor G is obtained by establishing a proportional rolling mill workpiece model using a commercial finite element model and through simulation calculations, and its value ranges from [0, 0.2].

7. A method for pre-setting the roll gap leveling based on the shape of the head of the slab before rolling according to claim 4, characterized in that The drive side stiffness and the operating side stiffness are obtained through stiffness tests of the rolling mill. During the stiffness test, the rolling mill adopts step-by-step pressing - pressure maintaining - pressing treatment, and the unloading process also adopts step-by-step pressing - pressure maintaining - pressing treatment, and the pressing force needs to exceed 18000 kN.

8. A method for pre-setting the mill roll gap leveling based on the shape of the head of the slab before rolling according to claim 1, characterized in that, In S2, the side guide plate parameters include the side guide plate length.

9. A method for pre-setting the roll gap leveling based on the shape of the head of the slab before rolling according to claim 1, characterized in that, In S2, the rolling process parameters include the roll gap leveling calculation value of the current pass, the offset of the center point of the head of the slab to be rolled from the rolling centerline, the predicted rolling force of the current pass, the center distance between the hydraulic cylinders on both sides of the rolling mill, the drive side stiffness, the operating side stiffness, the strip width influence coefficient, the width of the rolled strip, the length of the roll surface, and the strip transverse flow factor.

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