Universal rolling mill with variable-diameter upper and lower rollers and independent transmission function and control method thereof

Abstract

The invention relates to an upper and lower roller reducing independent transmission universal rolling mill and a control method thereof, and belongs to the technical field of metallurgy. The rolling mill comprises a universal rolling rough rolling unit, a middle rolling unit and a universal rolling finish rolling unit which are sequentially arranged along a rolling line, a horizontal roller set of each unit is of an upper and lower roller reducing structure and is provided with an independent transmission system, and a gearbox and a transmission shaft are driven by an independent motor to achieve roller separation control. The middle rolling unit is a reducing edging mill, and temperature control units are arranged in front of and behind the rough rolling unit and the finish rolling unit respectively. The rolling method comprises the steps of adjusting the roller diameter ratio, synchronously adjusting the dip angle of the universal spindle and the basic height of the rolling mill, conducting gradient deformation rolling, dynamically adapting to a rolling model and the like. Through cooperation of independent transmission and reducing, accurate matching of the speeds of the upper roller and the lower roller is achieved, deformation uniformity is improved, the total motor power is reduced, an adjustable cooling nozzle and intelligent model optimization are combined, a product has the surface layer ultra-fine grain structure and core toughness, and the yield and market competitiveness are remarkably improved.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgy, and relates to a universal rolling mill with upper and lower rolls with variable diameters and independent transmission and a control method thereof. Background Art

[0002] In the iron and steel metallurgical industry, steel sections, as steel with a specific cross-sectional shape, are widely used in the fields of construction, transportation, and machinery manufacturing. Its products are diverse, covering H-shaped steel, I-shaped steel, bulb flat steel, L-shaped steel, and various special-shaped cross-sectional profiles. The traditional steel section rolling process mainly relies on the ordinary two-roll rolling method and the four-roll universal rolling method, but in the production of asymmetric cross-sectional steel sections, the existing technology faces significant challenges. For example, when two-roll rolling is used, due to the uneven deformation in the hole type, the rolled piece is prone to produce large internal stress, resulting in defects such as "ears" and "folding", which seriously affects the efficiency of subsequent straightening, sawing and other processes. In addition, the uneven distribution of the upper and lower rollers during the rolling process can easily cause the rolled piece to bend, warp or buckle, further reducing the product yield and dimensional accuracy.

[0003] To solve the above problems, some companies use centralized transmission universal rolling mills for production. However, this technical solution has inherent limitations: first, the equal roller diameter design of the upper and lower rollers makes it impossible to adjust the rolling speed independently, making it difficult to match the differential deformation requirements of the upper and lower sections of asymmetric steel sections, exacerbating the bending problem of rolled pieces; second, centralized transmission requires matching high-power motors, and equipment investment and energy consumption costs are high; third, the upper and lower rollers have a fixed turning volume, and the rollers are frequently changed and consumed, increasing downtime and production costs. For example, in the final rolling process, skilled operators need to spend at least 1 hour to replace the rollers and guide devices, and the problem of low efficiency is particularly prominent. In addition, the existing rolling mills are not adaptable enough to asymmetric steel sections, which restricts the expansion of product types and market competitiveness.

[0004] In view of the above technical bottlenecks, there is an urgent need for a universal rolling mill that can realize independent transmission of upper and lower rolls, flexible and adjustable roll diameter, and strong process adaptability. Although there are explorations on the improvement of the transmission structure of rolling mills in the prior art, they generally fail to effectively solve the speed matching, energy consumption control and roll management problems in asymmetric rolling. For example, although some solutions try to adjust the roll parameters, they do not break through the framework of centralized transmission, resulting in uneven deformation penetration and poor stability of rolled parts; although other solutions propose the concept of split-roll transmission, they do not combine the variable diameter design with the intelligent control model, making it difficult to achieve efficient and low-consumption industrial production. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a universal rolling mill with upper and lower rolls with independent transmission and a control method thereof, and to provide a universal rolling mill with independent transmission, diameter change adaptation, dynamic temperature control and intelligent process optimization, so as to improve the production quality and efficiency of asymmetric steel sections.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A universal rolling mill with variable diameters of upper and lower rolls and independent drive includes a rough rolling unit for universal rolling, an intermediate rolling unit, and a finish rolling unit for universal rolling, which are arranged in sequence along the rolling line;

[0008] The horizontal roll sets of the rough rolling unit for universal rolling and the finish rolling unit for universal rolling are each composed of an upper roll and a lower roll. The diameter ratio of the upper roll to the lower roll is 0.3 - 2.5, and they are respectively driven by independent drive systems;

[0009] The independent drive system includes:

[0010] An upper roll gearbox and a lower roll gearbox, which are respectively connected to the upper roll and the lower roll through transmission shafts;

[0011] An upper roll motor and a lower roll motor, which respectively drive the corresponding gearboxes through transmission shafts;

[0012] The intermediate rolling unit is an edger, and the upper and lower rolls of its horizontal roll set adopt a variable diameter structure and are driven by a single motor;

[0013] The total number of frames of the rough rolling unit for universal rolling, the intermediate rolling unit, and the finish rolling unit for universal rolling is 3 - 5 frames, and each unit is equipped with 3 - 5 sets of auxiliary equipment.

[0014] Optionally, the rolling mill further includes: a pre - temperature control unit for universal rolling arranged in front of the rough rolling unit for universal rolling; a post - temperature control unit for universal rolling arranged behind the finish rolling unit for universal rolling; the number of temperature control devices in the temperature control unit is 0 - 10.

[0015] Optionally, in the independent drive system: the speed ratio of the upper roll gearbox and the lower roll gearbox is the same or different;

[0016] The power of the upper roll motor and the lower roll motor is the same or different, and a smaller roll diameter corresponds to a smaller - power motor, while a larger roll diameter corresponds to a larger - power motor.

[0017] Optionally, the rolling mill foundation is provided with a hydraulic cylinder compensation system for adjusting the position of the rolling mill foundation up and down, and the rolling center line remains unchanged before and after adjustment.

[0018] Optionally, the rolling mill further includes: a universal joint shaft inclination synchronous adjustment mechanism for adapting to the upper and lower rolls after diameter change; a hydraulic locking or disc spring mechanism for axially locking the rolls; a roll cooling mechanism with adjustable cooling nozzle angles, and the adjustment range of the nozzle angle is 15 - 75°.

[0019] Optionally, the rolling mill further includes a lubrication system for dynamically adjusting the lubricating oil flow rate and pressure of the roll bearings according to the diameter change of the upper and lower rolls.

[0020] Optionally, the rolling mill integrates the following control models: an asymmetric rolling force model for adjusting rolling parameters according to the roll diameter change; a shape control model and a post-rolling flatness model for adapting to the rolling process after the diameter change.

[0021] Optionally, the following strategy is adopted for setting the rotational speeds of the upper and lower rolls:

[0022] 1) Calculate the basic rotational speed ratio according to the roll diameter difference diameter ratio D u / D l , where D u is the upper roll diameter and D l is the lower roll diameter;

[0023] Set the motor rotational speeds of the initial upper and lower rolls through the formulas V u =πD u *n u , V l =πD l *n l , where V u is the upper roll linear speed, n u is the upper roll rotational speed, V l is the lower roll linear speed, and n l is the lower roll rotational speed;

[0024] 2) Detect the post-rolling flatness through a post-rolling laser flatness gauge and dynamically correct the motor rotational speeds of the upper and lower rolls, with the rotational speed of the smaller roll as the reference when correcting the rotational speeds;

[0025] 3) Establish a double closed-loop model of rolling force - linear speed, and dynamically correct the rotational speed through the formula n u =D u / D l *n l +α·(F u -F l ), where α is the rolling force compensation coefficient with a value range of 0 to 2 to solve the problem of rolling force imbalance caused by diameter differences;

[0026] The asymmetric rolling force model includes an upper roll rolling force model F u and a lower roll rolling force model F l ;

[0027] The upper roll rolling force model F u is:

[0028] F u =P·S u

[0029] S u =l u ·B

[0030] lu = sqrt(△h·D u / 2)

[0031] △h = h0 - h1

[0032] h p = (h0 + h1) / 2;

[0033] Where, S u is the upper roll contact area, in mm 2 , B is the width of the rolled piece, in mm, h0 is the entrance height, in mm, h1 is the exit height, in mm, △h is the difference between the entrance height and the exit height, in mm, h p is the average of the entrance height and the exit height, in mm, P is the unit deformation resistance of the material, in MPa, l u is the contact arc length of the upper roll, in mm;

[0034] (1) When :

[0035]

[0036] (2) When :

[0037]

[0038] σ - Deformation resistance of the material, in MPa;

[0039] t - Deformation temperature, in °C;

[0040] σ0 - Reference deformation resistance, in MPa;

[0041] a1,..., a6 - Regression coefficients, see the following table;

[0042] γ - Degree of deformation of logarithmic strain,

[0043] u - Deformation speed, in m / s

[0044] Upper roll rolling force:

[0045]

[0046] Lower roll rolling force model F u is:

[0047] F d = P·S d

[0048] S d = ld B

[0049] L d = sqrt(△h·D d / 2)

[0050] △h = h0 - h1

[0051] h p = (h0 + h1) / 2;

[0052] Among them, S d is the contact area of the lower roll, with the unit of mm 2 , B is the width of the rolled piece, with the unit of mm, h0 is the inlet height, with the unit of mm, h1 is the outlet height, with the unit of mm, △h is the difference between the inlet height and the outlet height, with the unit of mm, h p is the average value of the inlet height and the outlet height, with the unit of mm, P is the unit deformation resistance of the material, with the unit of MPa, l d is the contact arc length of the lower roll, with the unit of mm

[0053] (1) When :

[0054]

[0055] (2) When :

[0056]

[0057] Among them, the value ranges of σ0 to σ6 refer to the following table:

[0058] Steel grade <![CDATA[σ0]]> <![CDATA[a1]]> <![CDATA[a2]]> <![CDATA[a3]]> <![CDATA[a4]]> <![CDATA[a5]]> <![CDATA[a6]]> Q335 140～170 -2～3 0～4 0～1 -1～1 0～1 0～2 .

[0059] Optionally, the outlet rolling speed of the universal rolling finishing unit (5) of the rolling mill is 0.5 m / s to 10 m / s, which is suitable for producing asymmetric steel sections, including bulb flats, light rails, heavy rails and special-shaped steel sections.

[0060] A rolling method based on the above rolling mill includes the following steps:

[0061] Adjust the upper and lower roll diameter ratio to 0.3 to 2.5, and independently set the rolling speeds of the upper and lower rolls;

[0062] Synchronously adjust the universal joint angle and the rolling mill foundation height according to the roll diameter change to keep the rolling center line stable;

[0063] Adopt a variable roll diameter structure for gradient deformation rolling to form an ultrafine grain structure on the surface layer of the rolled piece and retain a ductile structure in the core;

[0064] The roll surface is uniformly cooled by a cooling nozzle with adjustable angle to control the thermal crown.

[0065] Dynamically adapt the rolling force model, tension model and stock shape model to optimize the rolling process of asymmetric steel sections.

[0066] The beneficial effects of the present invention are as follows:

[0067] Through the innovative structural design and rolling method of the universal mill with independent drive of upper and lower rolls with variable diameters, the present invention realizes significant performance improvement and process optimization in the production of asymmetric steel sections. The specific beneficial effects are as follows:

[0068] Improve rolling accuracy and product flatness

[0069] Through the independent drive system of the upper and lower rolls, the upper and lower rolls can adopt different speed ratios and power configurations respectively to achieve precise matching of speed and deformation. When rolling asymmetric steel sections, the independent adjustment of the speeds of the upper and lower rolls effectively avoids the bending, upward warping or buckling of the rolled piece caused by uneven elongation distribution. For example, for the rolling of heavy rails with a large thickness difference between the rail head and the rail bottom, the lower roll with a large roll diameter can be matched with a high-power motor to achieve a large reduction, while the upper roll uses a small-power motor for fine adjustment to ensure the through-train property and dimensional accuracy of the rolled piece. In addition, the hydraulic cylinder compensation system and the universal joint shaft inclination synchronous adjustment mechanism equipped on the mill foundation can automatically maintain the stability of the rolling center line after the diameter change, further ensuring the flatness and cross-section consistency of the rolled piece.

[0070] Reduce energy consumption and production costs

[0071] Adopt a variable-diameter structure combined with a split-roll drive strategy. The small roll diameter corresponds to a small-power motor, and the large roll diameter is adapted to a large-power motor. The total motor power is significantly reduced compared with the traditional centralized drive method. For example, when rolling bulb flats, the lower roll with a large roll diameter undertakes the main deformation, while the upper roll with a small roll diameter only needs to assist in forming, which can reduce the overall energy consumption. At the same time, the turning amounts of the upper and lower rolls can be set independently. After turning, the roll diameter ratio of 0.3 - 2.5 is still maintained, avoiding the waste of rolls caused by the fixed turning amount in centralized drive, prolonging the service life of the rolls and reducing the roll change frequency. This design can reduce the roll consumption, shorten the downtime, and significantly improve the production efficiency.

[0072] Enhance process adaptability and product diversity

[0073] The multi-frame collaborative layout of the universal rolling roughing unit, the intermediate edge rolling mill and the finishing unit (total number of frames: 3 to 5), combined with the wide speed range exit speed of 0.5 to 10 m / s, can flexibly adapt to the production needs of asymmetric steel sections of different specifications. For example, the high-speed mode is used to increase production capacity during light rail rolling, while the low-speed mode is used to ensure the forming accuracy of complex sections for special-shaped steel sections. The introduction of the temperature control unit (equipped with 0 to 10 temperature control devices) and the adjustable angle cooling nozzle (15 to 75°) further optimizes the temperature field distribution of the rolled piece, suppresses the loss of control of thermal convexity, and reduces surface cracks and oxide scale defects. It is especially suitable for materials that are sensitive to temperature control, such as high-strength steel and wear-resistant steel.

[0074] Improve equipment stability and intelligence

[0075] The rolling mill integrates rolling force model, tension calculation model and material type control model, and can adjust rolling parameters in real time according to the change of roller diameter. For example, after the diameter is changed, the system automatically adapts the rolling force distribution to avoid equipment loss caused by local overload. The lubrication system dynamically distributes the lubricating oil flow and pressure according to the diameter of the upper and lower rollers to ensure consistent bearing lubrication effect and extend the life of key components. In addition, the hydraulic locking or disc spring mechanism enhances the reliability of the axial fixation of the roller, reduces vibration and deviation during rolling, and ensures the stability of continuous production.

[0076] Improve material structure performance and product competitiveness

[0077] Through the gradient deformation rolling process, the variable roller diameter design allows the surface of the rolled piece to withstand a large amount of pressure reduction, promoting the formation of ultrafine grain structure, while the core maintains a tough structure. For example, when rolling high-speed heavy rails, the rail head area is subjected to high pressure through a large roller diameter and long contact arc, effectively refining the microstructure grain size of the rail head, significantly improving the hardness and wear resistance of the rail head; at the same time, the core retains toughness to avoid the risk of brittle fracture. This technology enables the finished product to have both high surface strength and overall toughness, expanding the market application space for high value-added products.

[0078] Promoting green manufacturing and sustainable development

[0079] The split-roll transmission strategy and energy consumption optimization design reduce energy consumption per ton of steel. Combined with the efficient thermal management of the temperature control unit, the overall energy consumption is significantly lower than that of traditional processes. The extended life of the rolls and the reduction of consumables further reduce resource waste, which is in line with the concept of green manufacturing. In addition, the application of intelligent models reduces the number of trial rollings and the scrap rate, improves the yield rate, and helps enterprises achieve low-carbon and efficient production.

[0080] In summary, the present invention achieves a comprehensive improvement in precision, efficiency, energy consumption and product quality in the production of asymmetric steel sections through structural innovation and process coordination, and has significant economic benefits and industry promotion value.

[0081] Other advantages, objects, and features of the present invention will be set forth in part in the following description, and in part will be obvious to those skilled in the art from a study of the following, or may be learned from practice of the invention. The objects and other advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

[0082] In order to make the objectives, technical solutions, and advantages of the present invention more clear, the present invention will be described in detail preferably with reference to the accompanying drawings, where:

[0083] Figure 1 is the general layout drawing of the universal rolling mill with variable diameters of the upper and lower rolls of the present invention;

[0084] Figure 2 is the schematic diagram of the upper and lower rolls driven by a separate motor of the present invention;

[0085] Figure 3 is the schematic diagram of the variable diameters of the upper and lower rolls of the present invention;

[0086] Figure 4 is the schematic diagram of the bending of the rolled product when the upper and lower rolls have equal diameters;

[0087] Figure 5 is the schematic diagram of the rolling of asymmetric section steel of the present invention;

[0088] Reference numerals: 1 pre-control temperature unit for universal rolling, 2 rough rolling unit for universal rolling, 3 intermediate rolling unit, 4 intermediate rolling unit, 5 finishing rolling unit for universal rolling, 6 post-control temperature unit for finishing rolling of universal rolling, 201-1 upper roll of the universal rolling mill, 201-2 transmission shaft between the upper roll and the gearbox, 201-3 upper roll gearbox, 201-4 transmission shaft between the upper roll gearbox and the motor, 201-5 upper roll motor, 202-1 lower roll of the universal rolling mill, 202-2 transmission shaft between the lower roll and the gearbox, 202-3 lower roll gearbox, 202-4 transmission shaft between the lower roll gearbox and the motor, 202-5 lower roll motor, 203-1 left roll of the universal rolling mill, 203-2 fixing mechanism for the left roll of the universal rolling mill, 204-1 right roll of the universal rolling mill, 204-2 fixing mechanism for the right roll of the universal rolling mill, 201-3-1 input shaft, 201-3-2 output shaft, 201-3-3 gear, 202-3-1 input shaft, 202-3-2 output shaft, 202-3-3 gear, 301-1 upper roll of the intermediate rolling mill, 301-2 transmission shaft between the upper roll and the gearbox, 301-3 upper roll gearbox, 301-4 transmission shaft between the upper roll gearbox and the motor, 301-5 upper roll motor, 302-1 lower roll of the intermediate rolling mill, 302-2 transmission shaft between the lower roll and the gearbox, 302-3 lower roll gearbox, 302-4 transmission shaft between the lower roll gearbox and the motor, 302-5 lower roll motor. Detailed implementation mode

[0089] The following specific examples are used to illustrate the implementation mode of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation modes. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the drawings provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0090] Among them, the drawings are only for illustrative purposes, showing only schematic diagrams, not physical diagrams, and should not be construed as a limitation to the present invention; in order to better illustrate the embodiments of the present invention, some components in the drawings will be omitted, enlarged or reduced, which does not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0091] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "rear", etc. indicating the orientation or positional relationship, they are based on the orientation or positional relationship shown in the accompanying drawings. This is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the accompanying drawings are only for illustrative purposes and should not be construed as a limitation of the present invention. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0092] Please refer to Figures 1 to 5 , which is a universal rolling mill with variable diameters of upper and lower rolls and independent drives. Please refer to Figure 1 . In this embodiment, the universal rolling roughing unit 2, intermediate rolling unit 3 or 4, universal rolling finishing unit 5, and post-finishing temperature control unit 6 of the universal rolling mill with variable diameters of upper and lower rolls and independent drives are arranged in sequence along the rolling line. Among them, the total number of stands of the universal rolling roughing unit 2, intermediate rolling unit 3 or 4, and universal rolling finishing unit 5 is 3 to 5 stands, and each unit is equipped with 3 to 5 sets of auxiliary equipment to ensure efficient coordination during the rolling process.

[0093] Detailed description of the rolling mill structure

[0094] Universal rolling roughing unit 2

[0095] As shown in Figure 2 and Figure 3 , the universal rolling roughing unit 2 includes an upper drive unit 201, a lower drive unit 202, a left vertical roll drive unit 203, and a right vertical roll drive unit 204.

[0096] Upper drive unit 201:

[0097] The upper roll 201-1 is connected to the upper roll gearbox 201-3 through a transmission shaft 201-2. The input shaft 201-3-1 of the gearbox is driven by a motor 201-5 through a transmission shaft 201-4. The gear on the input shaft 201-3-1 in the gearbox meshes with the gear 201-3-3 on the output shaft 201-3-2 to achieve power transmission.

[0098] Lower drive unit 202:

[0099] The lower roll 202-1 is connected to the lower roll gearbox 202-3 through a transmission shaft 202-2. The input shaft 202-3-1 of the gearbox is driven by a motor 202-5 through a transmission shaft 202-4. The gear on the input shaft 202-3-1 in the gearbox meshes with the gear 202-3-3 on the output shaft 202-3-2 to complete power transmission.

[0100] Vertical roll drive units 203 and 204:

[0101] The left vertical roll 203-1 is installed through the fixing mechanism 203-2, and the right vertical roll 204-1 is installed through the fixing mechanism 204-2. Both are passive drive units to assist in the lateral forming of the rolled piece.

[0102] Roll diameter configuration:

[0103] The diameter ratio of the upper roll 201-1 to the lower roll 202-1 is 0.3 to 2.5, which can be flexibly adjusted according to the cross-section difference of the asymmetric section steel. For example, when rolling heavy rails, a large roll diameter is used for the lower roll to achieve a high reduction, and a small roll diameter is used for the upper roll for fine adjustment of deformation.

[0104] Intermediate rolling unit 3 or 4

[0105] The intermediate rolling unit is an edger, and the structures of its upper drive unit 301 and lower drive unit 302 are similar to those of the rough rolling unit:

[0106] The upper roll 301-1 is connected to the gearbox 301-3 through the transmission shaft 301-2 and is driven by the motor 301-5;

[0107] The lower roll 302-1 is connected to the gearbox 302-3 through the transmission shaft 302-2 and is driven by the motor 302-5.

[0108] The upper and lower rolls of the edger adopt a variable diameter structure, and the diameters can be the same or different, and are driven by separate motors to ensure the dimensional accuracy of the edge of the rolled piece.

[0109] Universal rolling finishing unit 5

[0110] The structure of the finishing unit is exactly the same as that of the rough rolling unit 2. The upper and lower rolls are independently driven, and the roll diameter ratio is maintained at 0.3 to 2.5, which is used for final cross-section forming and dimensional calibration.

[0111] Temperature control unit configuration

[0112] The pre-universal rolling temperature control unit 1 is set in front of the rough rolling unit 2 and is equipped with 0 to 10 temperature control devices for billet preheating or temperature equalization;

[0113] The post-universal rolling finishing temperature control unit 6 is set behind the finishing unit 5 and uniformly cools the rolled piece through adjustable-angle cooling nozzles (adjustment range 15 to 75°) to suppress thermal crown and reduce surface defects.

[0114] Mill collaborative working process

[0115] Rolling preparation stage

[0116] Set the upper and lower roll diameter ratio (0.3 - 2.5) according to the target section steel specifications, and independently adjust the power and speed ratio of the upper and lower roll motors 201 - 5 and 202 - 5. For example, the lower roll uses a high - power motor to match a large roll diameter, and the upper roll uses a low - power motor.

[0117] Adjust the height of the mill foundation through the hydraulic cylinder compensation system to ensure the stability of the rolling center line; synchronously adjust the inclination angle of the universal joint shaft to adapt to the roll system after the diameter change.

[0118] Rolling execution stage

[0119] After the billet is equalized in the pre - temperature control unit 1, it enters the rough rolling unit 2, and the upper and lower rolls are independently driven to achieve asymmetric deformation. For example, the rail head is rolled under high pressure by the lower roll 202 - 1 with a large roll diameter, and the rail bottom is assisted in forming by the upper roll 201 - 1 to avoid the bending of the rolled piece.

[0120] The intermediate rolling units 3 or 4 trim the edges of the rolled piece to ensure the through - strip property;

[0121] The finishing rolling unit 5 completes the final section calibration, and the outlet speed range is 0.5 m / s - 10 m / s to meet the accuracy requirements of different section steels.

[0122] Post - rolling treatment stage

[0123] The rolled piece is cooled in the post - temperature control unit 6 after finishing rolling, and the angle of the cooling nozzle is dynamically adjusted according to the roll diameter to ensure uniform cooling of the roll surface;

[0124] The lubrication system dynamically distributes the lubricating oil flow rate and pressure according to the diameter change of the upper and lower rolls to ensure the bearing life.

[0125] Key technological innovation points

[0126] Independent drive and diameter change coordination: The power of the upper and lower roll motors 201 - 5 and 202 - 5 is independently configured. Combined with the differential design of the roll diameter, the optimal matching of the deformation amount and energy consumption is achieved, and the total motor power is reduced by 20% - 30% compared with the centralized drive.

[0127] Intelligent process adaptation: The rolling mill integrates the rolling force model, tension calculation model and profile control model, and optimizes the parameters in real - time according to the roll diameter change. For example, the reduction distribution is automatically adjusted after the diameter change to avoid local overload.

[0128] Optimized roll management: The turning amount of the upper and lower rolls can be independently set, and the roll diameter ratio remains 0.3 - 2.5 after turning, reducing roll waste and lowering the roll changing frequency.

[0129] Application examples

[0130] Taking the high - speed heavy rail rolling as an example:

[0131] The rail head area is subjected to high-pressure rolling with a long contact arc by the lower roll 202-1 with a large roll diameter (diameter ratio of 2.5), which refines the grain size and improves the surface hardness;

[0132] The rail bottom is assisted in forming by the upper roll 201-1 (diameter ratio of 0.4), and the tough tissue is retained in the core to avoid brittle fracture;

[0133] The finishing exit speed is set at 8 m / s. Combined with the uniform cooling of the temperature control unit 6, the flatness error of the finished product is reduced.

[0134] The rotational speeds of the upper and lower rolls are set using the following strategy:

[0135] 1) Calculate the basic rotational speed ratio according to the roll diameter difference diameter ratio D u / D l where D u is the upper roll diameter and D l is the lower roll diameter;

[0136] Set the motor rotational speeds of the initial upper and lower rolls through the formulas V u =πD u *n u and V l =πD l *n l where V u is the upper roll linear speed, n u is the upper roll rotational speed, V l is the lower roll linear speed, and n l is the lower roll rotational speed;

[0137] 2) Detect the flatness after rolling through a post-rolling laser flatness meter and dynamically correct the motor rotational speeds of the upper and lower rolls. When correcting the rotational speeds, use the rotational speed of the smaller roll as the reference;

[0138] 3) Establish a double closed-loop model of rolling force - linear speed. Dynamically correct the rotational speed through the formula n u =D u / D l *n l +α·(F u -F l ) where α is the rolling force compensation coefficient with a value range of 0 to 2 to solve the problem of rolling force imbalance caused by diameter differences;

[0139] The asymmetric rolling force model includes the upper roll rolling force model F u and the lower roll rolling force model F l ;

[0140] The upper roll rolling force model F u is:

[0141] F u =P·Su

[0142] S u = l u ·B

[0143] l u = sqrt(△h·D u / 2)

[0144] △h = h0 - h1

[0145] h p = (h0 + h1) / 2;

[0146] Wherein, S u is the upper roll contact area, with the unit of mm 2 , B is the width of the rolled piece, with the unit of mm, h0 is the entrance height, with the unit of mm, h1 is the exit height, with the unit of mm, △h is the difference between the entrance height and the exit height, with the unit of mm, h p is the average value of the entrance height and the exit height, with the unit of mm, P is the unit deformation resistance of the material, with the unit of MPa, l u is the contact arc length of the upper roll, with the unit of mm;

[0147] (1) When :

[0148]

[0149] (2) When :

[0150]

[0151] σ - The deformation resistance of the material, with the unit of MPa;

[0152] t - The deformation temperature, with the unit of °C;

[0153] σ0 - The reference deformation resistance, with the unit of MPa;

[0154] a1,..., a6 - Regression coefficients, see the following table;

[0155] γ - The degree of deformation of logarithmic strain,

[0156] u - The deformation speed, with the unit of m / s

[0157] Upper roll rolling force:

[0158]

[0159] The lower roll rolling force model F u is:

[0160] F d = P·S d

[0161] S d = l d B

[0162] L d = sqrt(△h·D d / 2)

[0163] △h = h0 - h1

[0164] h p = (h0 + h1) / 2;

[0165] Wherein, S d is the contact area of the lower roll, with the unit of mm 2 , B is the width of the rolled piece, with the unit of mm, h0 is the inlet height, with the unit of mm, h1 is the outlet height, with the unit of mm, △h is the difference between the inlet height and the outlet height, with the unit of mm, h p is the average value of the inlet height and the outlet height, with the unit of mm, P is the unit deformation resistance of the material, with the unit of MPa, l d is the contact arc length of the lower roll, with the unit of mm

[0166] (1) When :

[0167]

[0168] (2) When :

[0169]

[0170] Wherein, the values of σ0 to σ6 refer to the following table:

[0171] Steel grade <![CDATA[σ0]]> <![CDATA[a1]]> <![CDATA[a2]]> <![CDATA[a3]]> <![CDATA[a4]]> <![CDATA[a5]]> <![CDATA[a6]]> Q335 152 -2.711 3.347 0.2525 -0.1957 0.4598 1.556 .

[0172] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the present technical solution, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A universal rolling mill with variable diameters of upper and lower rolls and independent drives, characterized in that, It includes a universal rough rolling unit (2), an intermediate rolling unit (3, 4), and a universal finishing rolling unit (5) arranged in sequence along the rolling line; The horizontal roll sets of the universal rough rolling unit (2) and the universal finishing rolling unit (5) are both composed of an upper roll (201-1) and a lower roll (202-1). The diameter ratio of the upper roll to the lower roll is 0.3 to 2.5, and they are respectively driven by independent drive systems; The independent drive system includes: An upper roll gearbox (201-3) and a lower roll gearbox (202-3), which are respectively connected to the upper roll (201-1) and the lower roll (202-1) through transmission shafts (201-2, 202-2); An upper roll motor (201-5) and a lower roll motor (202-5), which respectively drive the corresponding gearboxes through transmission shafts (201-4, 202-4); The intermediate rolling unit (3, 4) is an edger, and the upper and lower rolls of its horizontal roll set adopt a variable diameter structure and are driven by a separate motor; The total number of frames of the universal rough rolling unit (2), the intermediate rolling unit (3, 4), and the universal finishing rolling unit (5) is 3 to 5 frames, and each unit is equipped with 3 to 5 sets of auxiliary equipment.

2. The rolling mill according to claim 1, characterized in that, It also includes: A universal pre-rolling temperature control unit (1) arranged in front of the universal rough rolling unit (2); A universal finishing rolling post-temperature control unit (6) arranged behind the universal finishing rolling unit (5); The number of temperature control devices of the temperature control unit is 0 to 10.

3. The rolling mill according to claim 1, characterized in that, In the independent drive system: The speed ratio of the upper roll gearbox (201-3) and the lower roll gearbox (202-3) is the same or different; The power of the upper roll motor (201-5) and the lower roll motor (202-5) is the same or different, and a smaller roll diameter corresponds to a smaller power motor, and a larger roll diameter corresponds to a larger power motor.

4. The rolling mill according to claim 1, characterized in that, The rolling mill foundation is provided with a hydraulic cylinder compensation system for adjusting the position of the rolling mill foundation up and down, and the rolling center line remains unchanged before and after adjustment.

5. The rolling mill according to claim 1, characterized in that, The rolling mill also includes: A universal joint shaft inclination synchronous adjustment mechanism for adapting to the upper and lower rolls after diameter change; A hydraulic locking or disc spring mechanism for axially locking the rolls; A roll cooling mechanism with adjustable cooling nozzle angles, and the adjustment range of the nozzle angle is 15 to 75°.

6. The rolling mill according to claim 1, characterized in that, The rolling mill also includes a lubrication system for dynamically adjusting the lubricating oil flow and pressure of the roll bearings according to the diameter change of the upper and lower rolls.

7. The rolling mill according to claim 1, characterized in that, The rolling mill integrates the following control models: An asymmetric rolling force model for adjusting rolling parameters according to roll diameter changes; A stock shape control model and a post-rolling flatness model for adapting to the rolling process after diameter change.

8. The rolling mill according to claim 1, characterized in that, The following strategy is adopted for setting the rotational speeds of the upper and lower rolls: 1) Calculate the basic rotational speed ratio according to the roll diameter difference diameter ratio D u / D l where D u is the upper roll diameter, and D l is the lower roll diameter; Through the formula V u = πD u *n u 、V l = πD l *n l Set the motor speeds of the initial upper and lower rollers, where V u is the linear speed of the upper roller, n u is the rotational speed of the upper roller, V l is the linear speed of the lower roller, n l is the rotational speed of the lower roller; 2) Detect the post-rolling flatness through a post-rolling laser flatness meter, and dynamically correct the motor rotational speeds of the upper and lower rolls. When correcting the rotational speeds, use the rotational speed of the smaller roll as the reference; 3) Establish a double closed-loop model of rolling force - line speed, and dynamically correct the rotational speed through the formula n u = D u / D l * n l + α · (F u - F l ), where α is the rolling force compensation coefficient, with a value range of 0 to 2, to solve the problem of rolling force imbalance caused by diameter differences; Asymmetric rolling force model, including the upper roll rolling force model F u and the lower roll rolling force model F l ; Upper roll rolling force model F u is as follows: F u = P·S u S u = l u · B l u = sqrt(△h·D u / 2) △h = h0 - h1 h p = (h0 + h1) / 2; Among them, S u is the upper roll contact area, with the unit of mm 2 , B is the width of the rolled piece, with the unit of mm, h0 is the entrance height, with the unit of mm, h1 is the exit height, with the unit of mm, △h is the difference between the entrance height and the exit height, with the unit of mm, h p is the average value of the entrance height and the exit height, with the unit of mm, P is the unit deformation resistance of the material, with the unit of MPa, l u is the contact arc length of the upper roll, with the unit of mm; (1) When : (2) When : σ - The deformation resistance of the material, unit: MPa; t - transformation temperature, unit: °C; σ0 - The reference deformation resistance, unit: MPa; a1,..., a6 - Regression coefficients, see the following table; Degree of deformation of γ-logarithmic strain u - Deformation speed, unit: m / s The rolling force of the upper roll: Lower roll rolling force model F u is as follows: F d = P·S d S d = l d B L d = sqrt(△h·D d / 2) △h = h0 - h1 h p = (h0 + h1) / 2; Among them, S d is the contact area of the lower roll, with the unit of mm 2 , B is the width of the rolled piece, with the unit of mm, h0 is the entrance height, with the unit of mm, h1 is the exit height, with the unit of mm, △h is the difference between the entrance height and the exit height, with the unit of mm, h p is the average value of the entrance height and the exit height, with the unit of mm, P is the unit deformation resistance of the material, with the unit of MPa, l d is the contact arc length of the lower roll, with the unit of mm; (1) When : (2) When : Among them, the value ranges of σ0 to σ6 refer to the following table: 。 9. The rolling mill according to claim 1, characterized in that, The outlet rolling speed of the universal rolling finishing mill unit (5) of the rolling mill is 0.5 m / s to 10 m / s, which is suitable for the production of asymmetric section steels, including bulb flats, light rails, heavy rails and special-shaped section steels.

10. A rolling method for a rolling mill according to any one of claims 1 to 9, characterized in that, It includes the following steps: Adjust the upper and lower roll diameter ratio to 0.3 to 2.5, and independently set the rolling speeds of the upper and lower rolls; Synchronously adjust the inclination angle of the universal coupling shaft and the height of the rolling mill foundation according to the roll diameter change to keep the rolling center line stable; Adopt a variable roll diameter structure for gradient deformation rolling to form an ultrafine grain structure on the surface layer of the rolled piece and retain a ductile structure in the core; Uniformly cool the roll surface through a cooling nozzle with an adjustable angle to control the thermal crown; Dynamically adapt the rolling force model, tension model and profile model to optimize the rolling process of asymmetric section steels.

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