Slab camber head control method and system based on rolling speed

Abstract

The application discloses a slab head buckling control method based on rolling speed, comprising: obtaining the current pass sled coefficient, and calculating the effective length of the sled coefficient; after the slab enters the rolling mill, the roller speed of the upper and lower rollers is controlled based on the sled coefficient; the target roller speed difference of the upper and lower rollers under the current rolling speed and the adjustment duration thereof are calculated, after the length of the slab mill entering the rolling mill reaches the effective length of the sled effect, the roller speed difference is adjusted to the target roller speed difference; after the duration of keeping the roller speed difference of the upper and lower rollers as the target roller speed difference reaches the adjustment duration, the roller speed of the upper and lower rollers is cut to maintain the load balance until the current pass rolling is completed. The sled coefficient effective time is determined through the rolling speed and the slab head buckling height, the effective control of the slab head buckling is realized, and the operator intervention rate is reduced; after the sled coefficient effective time, the upper and lower roller speeds are controlled to realize the slab buckling, so that the slab head meets the needs of the field production, and has important significance for subsequent fine rolling, steel biting and belt wearing.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of slab rolling, and relates to a slab buckle head control method and system based on rolling speed. BACKGROUND

[0002] The steel industry is one of the important components of modern industry, and slabs, as important raw materials for many industries in the national economy, account for nearly 40% of the total steel consumption. With the rapid development of ship port machines, bridge construction, aerospace, automobiles and home appliances, the demand for slabs has increased dramatically. However, during the slab rolling process, due to the influence of asymmetric plate shape factors, asymmetric plate shape defects may occur, which are manifested as camber in rough rolling. This not only reduces the product yield and the service life of the equipment, but also may affect the production stability and even cause safety hazards.

[0003] According to statistics, about 30% to 50% of the total scrap steel is caused by asymmetric plate shape defects during the rolling production process every year, resulting in serious resource waste and economic loss, which is a worldwide problem that has attracted widespread attention from production enterprises and research fields.

[0004] Currently, the control of the buckle head is based on the observation of the slab buckling height by the operator, and the upper and lower roll speed ratios are modified before the slab enters the rolling mill, so as to achieve the effect of controlling the plate shape. In actual production process, the above-mentioned control of the buckle head greatly depends on the operating experience of the operator, and therefore, the regulation and control of the buckle head are prone to cause accidents of collision between the slab and the rolling equipment. SUMMARY

[0005] The present application provides a slab buckle head control method based on rolling speed, aiming to improve the above-mentioned problems.

[0006] The present application is implemented as follows: a slab buckle head control method based on rolling speed, the method comprising the following steps:

[0007] (1) obtaining the current pass sled coefficient, calculating the effective length H of the sled coefficient SKI ;

[0008] (2) after the slab enters the rolling mill, controlling the roll speed of the upper and lower rolls based on the sled coefficient, and the lower roll speed is faster than the upper roll speed:

[0009] (3) calculating the target roll speed difference of the upper and lower rolls under the current rolling speed and the adjustment time T0, and after the length of the slab mill entering the rolling mill reaches the effective length H of the sled effect SKI , the roll speed difference of the upper and lower rolls is adjusted to the target roll speed difference;

[0010] (4) After the length of maintaining the roll speed difference between the upper and lower rolls as the target roll speed difference reaches the adjustment length T0, the roll speed is cut to maintain the load balance until the current pass rolling is completed.

[0011] Further, the effective length H of the sledging coefficient is calculated as follows: SKI The calculation formula is as follows:

[0012]

[0013] Wherein, L pre is the slab warping height of the previous pass; h0 is the slab length of the current pass; β is the effective length coefficient.

[0014] Further, the calculation formula of the target roll speed difference Δv1 is as follows:

[0015] Δv1=Δv pre -ΔQ K ;

[0016] Wherein, Δv pre is the current roll speed difference between the upper and lower rolls of the rolling mill; ΔQ K is the roll speed difference adjustment amount of the rolling mill at the current rolling speed.

[0017] Further, the calculation formula of the roll speed difference adjustment amount ΔQ K is as follows:

[0018]

[0019] Wherein, L is the slab warping height of the current pass; F up is the upper roll rolling force; F down is the lower roll rolling force; γ is the warping decay coefficient.

[0020] Further, the adjustment length T0 of the target roll speed difference Δv1 is obtained as follows:

[0021] (31) Calculate the speed control length d0 of the current pass;

[0022] (32) Calculate the speed control length d0 under the speed control length d0 based on the current rolling speed. The speed control length is the adjustment length T0.

[0023] Further, the calculation formula of the speed control length d0 of the current pass i is as follows:

[0024]

[0025] Wherein, t0 is the rolling time of the previous pass; v0 is the rolling speed of the current pass; h0 is the slab length of the current pass, and H iH is an odd pass influence factor, and H i H is an even pass influence factor.

[0026] Further, H q =2, H o =3.

[0027] The present application is achieved in a slab head buckling control system based on rolling speed, the system comprises:

[0028] An input unit and a processor;

[0029] The input unit inputs the sledging coefficient of the current pass to the processor, and the processor adjusts the roll speed of the upper roll and the lower roll of the rolling mill based on the slab head buckling control method based on the rolling speed.

[0030] Further, the processor is in communication connection with the PLC controller of the primary system, and the processor reads the slab buckling height L pre of the previous pass, the slab length h0 of the current pass, the slab buckling height L of the current pass, the rolling force F up of the upper roll, the rolling force F down of the lower roll, the rolling time t0 of the previous pass and the rolling speed v0 of the current pass from the PLC controller of the primary system.

[0031] The slab head buckling control method based on the rolling speed has the following beneficial effects:

[0032] The sledging coefficient effective time is determined by the rolling speed and the slab head buckling height, the effective control of the slab head buckling is realized, the operator intervention rate is reduced, the upper and lower roll speeds are controlled after the sledging coefficient effective time to realize the slab buckling, so that the slab head meets the needs of the field production, which is of great significance to the subsequent precision rolling, belt wearing and other links, improves the rolling stability and the accuracy of the shape control, realizes the automatic control of the slab head buckling, and improves the hot rolling quality. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 The slab head buckling control method based on the rolling speed provided by the embodiment of the present application is shown in the flowchart. DETAILED DESCRIPTION

[0034] The specific embodiments of the present application will be further described in detail below with reference to the drawings, and the specific embodiments of the present application will be further described in detail below with reference to the drawings, to help those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present application.

[0035] After the slab enters the rolling mill, the roller speed of the upper and lower rollers is adjusted based on the sled coefficient, and the lower roller speed is set to be faster than the upper roller speed, at which time the slab shows a head kick; after the slab enters the rolling mill for a length of H SKI , in order to prevent the head kick from being too high to hit the equipment, the roller speed difference of the upper and lower rollers is controlled to make the upper roller speed faster than the lower roller speed, the slab shows a head kick, and after the speed control length d0 is maintained, at which time the slab body is rolled, the rolling condition tends to be stable, and therefore the roller speed difference of the upper and lower rollers is controlled based on load balance to the current pass rolling end.

[0036] Figure 1 A slab head kick control method based on rolling speed is provided in the embodiment of the present application, and the method is as follows:

[0037] (1) The current pass sled coefficient is obtained, and the effective length H SKI of the sled coefficient is calculated.

[0038] Before the current pass rolling starts, the current pass sled coefficient is set and issued by the site operator according to experience and the slab head kick bending height on site.

[0039] In the embodiment of the present application, the calculation formula of the effective length H SKI of the sled coefficient is as follows:

[0040]

[0041] Wherein, L pre is the slab bending height of the previous pass, with a unit of m, obtained through a primary system; h0 is the slab length of the current pass, with a unit of m, obtained through a primary system; β is a coefficient, determined by the actual production situation on site, and generally takes a value of 0.02.

[0042] (2) After the slab enters the rolling mill, the roller speed of the upper and lower rollers is controlled based on the sled coefficient, and the lower roller speed is controlled to be faster than the upper roller speed:

[0043] If the slab head shows a head kick, it will cause an impact on the roller, and in severe cases, the slab will be stuck in the roller. Therefore, after the slab enters the rolling mill, the roller speed of the upper and lower rollers is adjusted based on the sled coefficient, and the upper roller or the lower roller is specifically adjusted according to the specific setting of the on-site primary program logic, and the lower roller speed is set to be faster than the upper roller speed, at which time the slab shows a head kick.

[0044] (3) The target roller speed difference of the upper and lower rollers at the current rolling speed and the adjustment time T0 are calculated, and after the length of the slab mill entering the rolling mill reaches the effective length H SKI of the sled effect, the roller speed difference of the upper and lower rollers is adjusted to the target roller speed difference;

[0045] In the embodiment of the present application, the calculation formula of the target roller speed difference Δv1 is as follows:

[0046] Δv1=Δv pre -ΔQ K ;

[0047] Wherein, Δv pre is the current roll speed difference of the rolling mill, unit: m / s, obtained through a primary system; ΔQ K is the roll speed difference adjustment amount of the rolling mill under the current rolling speed.

[0048] In the embodiment of the application, the calculation formula of the roll speed difference adjustment amount ΔQ K is as follows:

[0049]

[0050] Wherein, L is the slab warping height of the current pass, unit: m, obtained through a primary system; F up is the upper roll rolling force, unit: kN, obtained through a primary system; F down is the lower roll rolling force, unit: kN, obtained through a primary system; γ is the warping attenuation coefficient, determined according to different steel grades and thicknesses on site.

[0051] In the embodiment of the application, the adjustment time length T0 of the target roll speed difference Δv1 is obtained as follows:

[0052] (31) Calculate the current pass speed control length d0;

[0053] In order to prevent the slab from colliding with the descaling water cover at the outlet of the rolling mill when rolling the odd pass, and in order to prevent the slab from colliding with the vertical roll of the rolling mill when rolling the even pass, different speed control lengths are set for rolling the odd and even passes, so as to achieve the effect of protecting the rolling equipment.

[0054] Since there is a genetic relationship between the rolling lengths of adjacent passes of the slab, the speed control length of the current pass is calculated by using the rolling time of the previous pass, and the calculation formula is as follows:

[0055]

[0056] Wherein, t0 is the rolling time of the previous pass, unit: s, obtained through a primary system;

[0057] v0 is the rolling speed of the current pass, unit: m / s, obtained through a primary system;

[0058] h0 is the slab length of the current pass, unit: m, obtained through a primary system;

[0059] H iH is an odd pass influence factor, unit: m, H i H is an odd pass influence factor, unit: m, H q H is an odd pass influence factor, unit: m, H i H is an odd pass influence factor, unit: m, H o H is an odd pass influence factor, unit: m, H

[0060] (32) The speed control length d0 is calculated based on the current rolling speed, and the speed control length is the adjustment time T0, and the calculation formula is as follows:

[0061]

[0062] (4) After the time length of maintaining the roll speed difference between the upper and lower rollers as the target roll speed difference reaches the adjustment time T0, the roll speed of the upper and lower rollers is cut to maintain the load balance, and the current pass rolling is ended.

[0063] The application also provides a slab camber head control system based on rolling speed, which comprises an input unit and a processor, the processor is in communication connection with a PLC controller of a primary system; the processor reads a last pass slab camber height L pre , a current pass slab length h0, a current pass slab camber height L, an upper roller rolling force F up , a lower roller rolling force F down , a last pass rolling time t0 and a current pass rolling speed v0 from the PLC controller of the primary system.

[0064] The current pass sled coefficient is input into the processor through the input unit, and the processor adjusts the roll speed of the upper and lower rollers of the current pass rolling mill based on the above slab camber head control method based on rolling speed.

[0065] The application is described exemplarily, and it is obvious that the specific implementation of the application is not limited by the above method, as long as various non-essential improvements are made by using the method concept and technical scheme of the application, or the concept and technical scheme of the application are directly applied to other occasions without improvement, which are all within the protection scope of the application.

Claims

1. A slab crooked head control method based on rolling speed, characterized by, The method comprises the following steps: (1) Obtain the current pass sledging coefficient, calculate the effective length H of the sledging coefficient SKI ; (2) After the slab enters the rolling mill, the roller speeds of the upper and lower rollers are controlled based on the sled coefficient, and the lower roller speed is faster than the upper roller speed: (3) calculating a target roll speed difference of the upper and lower rolls at the current rolling speed and a regulation time length T0 thereof, when the length of the slab mill entering the rolling mill reaches an effective length H of the ski effect SKI After that, the roll speed difference of the upper and lower rolls is regulated to the target roll speed difference; (4) After the time length of maintaining the roller speed difference between the upper and lower rollers as the target roller speed difference reaches the adjustment time length T0, the roller speeds of the upper and lower rollers are cut to maintain the load balance until the current pass rolling is completed; Effective length of the sled coefficient H SKI The calculation formula is as follows: wherein L pre is the slab camber height of the previous pass; h0is the slab length of the current pass; β is the effective length coefficient; The calculation formula of the target roller speed difference Δv1 is specifically as follows: Δv1 = Δv pre - ΔQ K ; wherein Δv pre is the current roll speed difference between the upper and lower rolls of the rolling mill; ΔQ K is the roll speed difference adjustment amount for the rolling mill at the current rolling speed; The adjustment time length T0 of the target roller speed difference Δv1 is obtained in the following manner: (31) Calculate the speed control length d0 of the current pass; (32) Calculate the speed control time length under the speed control length d0 based on the current rolling speed, and the speed control time length is the adjustment time length T0.

2. The slab camber head control method based on rolling speed according to claim 1, characterized by, Roll speed difference adjustment amount ΔQ K The calculation formula is as follows: Wherein, L is the slab warping height of the current pass; F up is the upper roll rolling force; F down is the lower roll rolling force; γ is the warping decay coefficient.

3. The slab camber head control method based on rolling speed according to claim 1, characterized by, The calculation formula of the speed control length d0 of the current pass i is specifically as follows: Wherein, t0 is the rolling time of the previous pass; v0 is the current pass rolling speed; h0 is the current pass slab length, H i is taken as the odd pass influence factor, and H i is taken as the even pass influence factor.

4. The slab camber head control method based on rolling speed according to claim 3, wherein, Odd order impact factor H q = 2, even order impact factor H o = 3.

5. A slab dog head control system based on rolling speed, characterized by, The system comprises: An input unit and a processor; The sled coefficient of the current pass is input into the processor through the input unit, and the processor adjusts the roller speeds of the upper and lower rollers of the current pass rolling mill based on the slab camber head control method based on the rolling speed according to any one of claims 1 to 4.

6. The slab camber head control system based on rolling speed according to claim 5, wherein, The processor is in communication connection with the PLC controller of the primary system, and the processor reads the slab warping height L of the previous pass, the current pass slab length h0, the slab warping height L of the current pass, the upper roll rolling force F pre , the lower roll rolling force F up , the rolling time t0 of the previous pass and the rolling speed v0 of the current pass from the PLC controller of the primary system. down , the rolling time t0 of the previous pass and the rolling speed v0 of the current pass from the PLC controller of the primary system.

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