Double-roller thin-strip continuous casting casting method and control system

Abstract

The invention belongs to the field of double-roller thin-strip continuous casting process control, and relates to a double-roller thin-strip continuous casting pouring method and a control system. Comprising the following steps that continuous casting parameters in the casting process are set, and the continuous casting parameters at least comprise a casting and rolling force upper limit Fupset, a casting and rolling force lower limit Fdown set, a target roll gap Starget and an initial roll surface speed V0; casting is started, a roll gap S is kept at a target roll gap Starget, and the liquid level height L of a molten pool and the actual casting and rolling force Factual are monitored in real time; and after the molten pool liquid level height L reaches a set value Lset, the molten pool liquid level height L is controlled to be stabilized in a target interval through a first closed-loop control loop related to the casting flow Q, and the casting and rolling force Facting is controlled to be stabilized in the target interval through a second closed-loop control loop formed by taking the casting and rolling force Facting and the roll surface speed Vacting as variables. According to the casting method, the problem of roll gap fluctuation caused by casting and rolling force fluctuation can be avoided, the adjusting process of the system is simplified through decoupling of liquid level closed-loop control and casting and rolling force-speed closed-loop control, and the stability and control precision of the system are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of twin-roller thin strip continuous casting process control, and relates to a twin-roller thin strip continuous casting start-casting method and a control system. Background Art

[0002] In the metal continuous twin-roll casting technology, the molten metal is directly poured into a pair of casting rolls rotating in opposite directions. In this process, the casting nozzle plate, the side sealing mechanism and the casting rolls together form a molten pool, in which the molten metal solidifies and rolls, and finally forms a thin strip. Specifically, Figure 1 As shown, Figure 1 The schematic diagram of the existing double-roller thin strip continuous casting process is shown in FIG. During the pouring process, a certain amount of molten metal is introduced from the chute 1 through the distributor 2 into the molten pool composed of the crystallization roller 4 and the side sealing plate. After the molten metal flows out of the distributor 2, it is directly sprayed onto the surface of the casting roller sleeve 4 of the casting roller 5 and rapidly solidifies to form a blank shell. As the casting roller 5 rotates, the solidified blank shell gradually thickens and converges at the lower end to form a fully solid casting strip 6. After rolling and forming, the casting strip 6 is sent to the subsequent area. The fragments at the beginning of pouring are collected in the waste hopper 7 at the bottom of the casting roller 5. When the strip is stably discharged, the casting strip 6 is transported to the pinch roller 8 through the movable arc guide plate. The casting strip after the pinch roller 8 is sent to the hot rolling mill 9 for one-pass rolling; the casting strip 6 after rolling in the hot rolling mill 9 is sent to the mobile shear 10 for head shearing; the casting strip 6 after shearing by the mobile shear 10 is sent to the end coiler 11 for coiling and collection. After the cast strip 6 is coiled on the coiler 11 for several turns, the cast strip 6 is successfully cast, and the unit switches to a stable production mode.

[0003] However, in the initial stage of casting, the casting rolls are in a cold state, the liquid level fluctuates greatly, and the entire unit is not stable. In the early stage of casting, since the casting rolls are still in a cold state, their surface temperature is much lower than the temperature of the metal solution, which causes the metal solution to solidify rapidly as soon as it contacts the roll surface. The faster solidification rate often causes violent fluctuations in the casting force. The instability of the casting force is directly transmitted to the roll gap, causing frequent and large changes in the roll gap width, which in turn has an adverse effect on the thickness uniformity, surface quality and even overall mechanical properties of the thin strip. What's more serious is that this instability may also induce serious accidents such as leakage, strip breakage, and jamming, which seriously hinders the rapid establishment of a stable casting state and greatly reduces production efficiency and yield.

[0004] In response to this problem, researchers and engineers have made unremitting explorations and attempts. Some early technical solutions, such as using a spring system to absorb the fluctuating energy of the casting force, or using a post-mounted thickness gauge in conjunction with a servo hydraulic system for dynamic thickness adjustment, have alleviated the thickness deviation problem to a certain extent, but none of them have touched upon the fundamental problem of large fluctuations in the casting force, and the problem of unstable roll gap still exists. As another strategy, the ingot bar pouring technology has indeed improved the success rate of the lead-in belt by introducing the ingot bar to increase the stability of the initial casting stage, but unfortunately, it has not effectively solved the risk of belt breakage or jamming caused by the surge in casting force. The multivariable control pouring method represents a more advanced technical idea. This method attempts to achieve closed-loop control of the casting force by precisely controlling parameters such as the initial roll gap size, roll speed, and applied pressure. Although this method can theoretically achieve more precise control, it not only requires extremely high initial condition setting accuracy, but also relies on a highly integrated control system. Before the system reaches a stable state, it often requires a long adjustment time, during which the system is prone to oscillation, affecting production continuity and product quality.

[0005] In summary, although there have been many attempts to solve the pouring problem in twin-roll casting, these methods have certain limitations and shortcomings. Problems such as large fluctuations in casting force and unstable roll gap in the initial stage of pouring have not been effectively solved. Summary of the invention

[0006] In view of this, the purpose of the present invention is to provide a twin-roller thin strip continuous casting method and control system, aiming to solve the problems of leakage, strip breakage, jamming, etc. caused by the sharp fluctuation of casting and rolling force during casting, and to improve the success rate of casting and casting efficiency.

[0007] In order to achieve the above object, the present invention provides the following technical solution: a twin-roller thin strip continuous casting method, comprising the following steps:

[0008] Set the continuous casting parameters during the pouring process. The continuous casting parameters at least include the upper limit of the casting force F. upset , lower limit of casting force F downset , target roll gap S target , initial roller surface speed V0;

[0009] Start casting and keep the roll gap S at the target roll gap S target , real-time monitoring of the molten pool liquid level L and the actual casting force F actual ;

[0010] When the molten pool liquid level L reaches the set value L set After that, the first closed-loop control loop related to the casting flow Q is used to control the molten pool liquid level L to be stable within the target range, and the second closed-loop control loop related to at most two continuous casting parameters is used to control the actual casting force F.actual Stable within the target range.

[0011] Optionally, the upper limit of the casting force F is calculated using the following formula: upset , lower limit of casting force F downset :

[0012]

[0013] Where, F is the casting force, kN; K is the deformation resistance, MPa; n σ is the stress state coefficient; B is the width of the casting strip, mm; R is the radius of the casting roll, mm; Δh is the reduction, mm;

[0014] The casting force F corresponding to the minimum Δh is F downset , the casting force F corresponding to the maximum Δh is F upset ;

[0015] The target roll gap S is calculated using the following formula: target :

[0016]

[0017] Where, S0 is the frame constant, mm; M is the casting machine stiffness, kN / mm; F actual is the actual casting force, kN;

[0018] The initial roll surface speed V0 is obtained by looking up a table, and different casting thicknesses correspond to different initial speeds.

[0019] Optionally, the casting flow rate at the beginning of casting is Q0, and the roller surface speed of the casting roller is V0; wherein Q0 is greater than the casting flow rate Q during stable production. actual .

[0020] Optionally, the following formula is used to calculate the casting flow rate Q during stable production: actual :

[0021] Q actual =V0×h×B×ρ

[0022] Where V0 is the initial roller surface speed, m / min; h is the casting strip thickness, mm; B is the casting strip width, mm; ρ is the casting strip density, kg / m 3 ;

[0023] The casting flow rate at the beginning of casting is Q0 = 1.5 × Q actual .

[0024] Optionally, a prestress F0 is applied to the casting rolls before casting to keep the roll gap S at the target roll gap S. target ; Prestress F0 = 1.2 × F upset .

[0025] Optionally, a prestress F0 for maintaining the roll gap at a target roll gap is applied to the casting rolls by pressing the movable casting roll bearing seat in a pair of casting rolls against the fixed casting roll bearing seat.

[0026] Optionally, the control logic of the first closed-loop control loop related to the casting flow rate Q is:

[0027] When the molten pool liquid level L is less than the set value L set When the casting flow rate is increased, the casting flow rate Q = Q0 + ΔQ;

[0028] When the molten pool liquid level L is greater than the set value L set When , the casting flow rate is reduced, and the casting flow rate Q = Q0-ΔQ.

[0029] Optionally, the molten pool liquid level L is controlled to be stable at L by a first closed-loop control circuit related to the casting flow Q. set Within ±2mm.

[0030] Optionally, the second closed-loop control loop is based on the actual casting force F actual and roller surface speed V actual As a closed-loop response control loop composed of variables.

[0031] Optional, with actual casting force F actual and roller surface speed V actual The control logic of the relevant second closed-loop control loop is:

[0032] When the actual casting force F actual Greater than the set value F set When the roller surface speed increases, the roller surface speed V actual+1 =V actual +ΔV;

[0033] When the actual casting force F actual Less than the set value F set When the roller surface speed is reduced, the roller surface speed V actual+1 =V actual -ΔV.

[0034] Optional, actual casting force F actual The target interval is (F upset , F downset ), F upset is the maximum casting force of the twin-roll caster, F downset The minimum casting force required to ensure that the outlet cast strip hangs naturally without breaking.

[0035] The present invention also provides a twin-roller thin strip continuous casting start-casting control system, comprising:

[0036] Pre-calculation module, used to calculate the continuous casting parameters during the pouring process, the continuous casting parameters at least include the upper limit of the casting force F upset , lower limit of casting force F downset , target roll gap S target , initial roller surface speed V0;

[0037] A control module, which sets continuous casting parameters based on the calculation results of the pre-calculation module and controls the continuous casting parameters during the pouring process;

[0038] Monitoring module, real-time monitoring of the molten pool liquid level L and actual casting force F during the casting process actual .

[0039] The control module includes a first control module and a second control module. The first control module is used to control the casting flow rate Q so that the molten pool liquid level L is stable within the target range; the second control module is used to control the roller surface speed V actual , so that the actual casting force F actual Stable within the target range;

[0040] Optionally, the continuous casting parameters calculated by the pre-calculation module during the pouring process include at least the upper limit of the casting force F upset , lower limit of casting force F downset , target roll gap S target , initial roller surface speed V0;

[0041] Optionally, the pre-calculation module calculates the continuous casting parameters of the pouring process according to the following model:

[0042] Optionally, the control module further includes a third control module, which is used to keep the roll gap S at the target roll gap S. target The third control mold drives the movable casting roll bearing seat in a pair of casting rolls to press against the fixed casting roll bearing seat, thereby applying a prestress F0 to the casting rolls to keep the roll gap S at the target roll gap S. target .

[0043] Optionally, when casting starts, the first control module controls the casting flow rate to Q0, and the second control module controls the roller surface speed of the casting roller to V0; wherein Q0 is greater than the casting flow rate Q during stable production. actual .

[0044] Optionally, when the monitoring module measures the molten pool liquid level L to reach the set value L set After that, the first control module controls the molten pool liquid level L to be stable within the target range through the first closed-loop control circuit related to the casting flow rate Q, and the second control module controls the actual casting force F through the second closed-loop control circuit related to at most two continuous casting parameters. actual Stable within the target range.

[0045] Optionally, the control logic of the first closed-loop control loop is:

[0046] When the molten pool liquid level L is less than the set value L set When the casting flow rate is increased, the casting flow rate Q = Q0 + ΔQ;

[0047] When the molten pool liquid level L is greater than the set value L set When the casting flow rate is reduced, the casting flow rate Q = Q0-ΔQ;

[0048] The first closed-loop control loop related to the casting flow Q controls the molten pool liquid level L to be stable at L set Within ±2mm.

[0049] Optionally, the second closed-loop control loop is based on the actual casting force F actual and roller surface speed V actual As a closed-loop response control loop composed of variables, the control logic of the second closed-loop control loop is:

[0050] When the actual casting force F actual Greater than the set value F set When the roller surface speed increases, the roller surface speed V actual+1 =V actual +ΔV;

[0051] When the actual casting force F actual Less than the set value F set When the roller surface speed is reduced, the roller surface speed V actual+1 =V actual -ΔV;

[0052] Actual casting force F actual The target interval is (F upset , F downset ), F upset is the maximum casting force of the twin-roll caster, F downset The minimum casting force required to ensure that the outlet cast strip hangs naturally without breaking.

[0053] The beneficial effects of the present invention are:

[0054] First, the present invention sets a fixed roll gap by applying prestress, which effectively avoids the roll gap fluctuation problem caused by casting force fluctuation during continuous casting. In the traditional casting process, the fluctuation of the roll gap often leads to a series of problems such as leakage, belt breakage and jamming, which seriously affects the production efficiency and product quality. However, the present invention significantly improves the stability of the pouring process by fixing the roll gap, reduces the incidence of the above problems, and thus improves the overall production efficiency and casting quality.

[0055] Secondly, the first closed-loop control loop and the second closed-loop control loop provided by the present invention successfully realize the decoupling of the liquid level closed-loop control and the casting force-speed closed-loop control, so that the three key parameters of liquid level, pressure and speed can be independently and accurately controlled without interfering with each other. This means that when adjusting a certain parameter, it will not have a significant impact on the other two parameters, thereby greatly simplifying the adjustment and control process of the system and improving the stability and control accuracy of the system.

[0056] Finally, the equipment system of the present invention is simple and efficient, making the pouring process easy to control and requiring no manual operation, which not only improves production efficiency but also enhances the safety of the operation process. In particular, during pouring, the flow rate is adjusted by the front-end control valve to quickly reach and stabilize the target liquid level. This design is simple and easy to use, and very practical, providing strong support for establishing a stable pouring process. In summary, the present invention provides an efficient, stable and easy-to-control pouring method and control system, which is of great significance for improving the efficiency and quality of the entire casting and rolling process.

[0057] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0059] Figure 1 It is a schematic diagram of the existing twin-roller thin strip continuous casting process;

[0060] Figure 2 A logic control diagram of a first closed-loop control circuit and a second closed-loop control circuit of a twin-roller thin strip continuous casting method provided by the present invention;

[0061] Figure 3 A variable change curve diagram of a second closed-loop control circuit of a twin-roller thin strip continuous casting method provided by the present invention.

[0062] Reference numerals:

[0063] 1-chute, 2-stopper rod, 3-distributor, 4-casting roller sleeve, 5-casting roller core, 6-casting strip, 7-waste hopper, 8-pinch roll, 9-hot rolling mill, 10-mobile shear, 11-coiler. DETAILED DESCRIPTION

[0064] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0065] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0066] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which 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 operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0067] During the continuous twin-roll casting and rolling of metal, the molten pool formed by the casting nozzle plate, the side sealing mechanism and the casting rolls can realize the solidification and rolling of the metal solution. However, in the early stage of casting, since the casting rolls are in a cold state, their surface temperature is much lower than the metal solution, which causes the metal solution to solidify rapidly and triggers violent fluctuations in the casting and rolling force. This instability not only affects the frequent and large changes in the roll gap width, and thus has an adverse effect on the thickness uniformity, surface quality and overall mechanical properties of the thin strip, but may also induce serious accidents such as leakage, strip breakage and jamming, which seriously hinders the rapid establishment of a stable casting and rolling state and reduces production efficiency and yield rate.

[0068] In response to this problem, although there have been many attempts to use spring systems, post-mounted thickness gauges in combination with servo hydraulic systems, ingot guide rod casting technology and multivariable control casting methods, these solutions have not been able to effectively solve the fundamental problem of large fluctuations in casting force and unstable roll gap. Some of them have limitations, or require extremely high initial condition setting accuracy and highly integrated control systems, and are prone to oscillations before the system stabilizes.

[0069] Therefore, the existing technology still has significant defects and cannot meet the needs of efficient and stable production. In view of this, the present invention proposes a twin-roller thin strip continuous casting method and control system, which aims to solve various problems caused by the sharp fluctuation of casting force during casting through innovative technical means, improve the success rate of casting and casting efficiency, thereby overcoming the shortcomings of the existing technology and promoting the further development of metal continuous twin-roller casting technology.

[0070] The present invention provides a twin-roller thin strip continuous casting method, comprising the following steps:

[0071] Step S1: Setting the continuous casting parameters of the pouring process, the continuous casting parameters at least include the upper limit of the casting force F upset , lower limit of casting force F downset , target roll gap S target , initial roller surface speed V0;

[0072] Step S2: Start casting and keep the roll gap S at the target roll gap S target , real-time monitoring of the molten pool liquid level L and the actual casting force F actual ;

[0073] Step S3: When the molten pool liquid level L reaches the set value L set After that, the first closed-loop control loop related to the casting flow Q is used to control the molten pool liquid level L to be stable within the target range, and the second closed-loop control loop related to at most two continuous casting parameters is used to control the actual casting force F. actual Stable within the target range.

[0074] In step S1, the upper limit of the casting force F is calculated using the following formula: upset , lower limit of casting force F downset :

[0075]

[0076] Where, F is the casting force, kN; K is the deformation resistance, MPa; n σ is the stress state coefficient; B is the width of the casting strip, mm; R is the radius of the casting roll, mm; Δh is the reduction, mm;

[0077] The casting force F corresponding to the minimum Δh is F downset , the casting force F corresponding to the maximum Δh is F upset ;

[0078] The target roll gap S is calculated using the following formula: target :

[0079]

[0080] Where, S0 is the frame constant, mm; M is the casting machine stiffness, kN / mm; Factual is the actual casting force, kN;

[0081] The initial roll surface speed V0 is obtained by looking up a table, and different casting thicknesses correspond to different initial speeds.

[0082] In step S2, the casting flow rate at the start of casting is Q0, and the roller surface speed of the casting roll is V0. Q0 is greater than the casting flow rate Q during stable production. actual , so that the molten pool liquid level L can quickly reach the set value L set The casting flow rate Q during stable production is calculated using the following formula: actual :

[0083] Q actual =V0×h×B×ρ

[0084] Where V0 is the initial roller surface speed, m / min; h is the casting strip thickness, mm; B is the casting strip width, mm; ρ is the casting strip density, kg / m 3 ;

[0085] The casting flow rate at the beginning of casting is Q0 = 1.5 × Q actual .

[0086] In step S2, a prestress F0 is applied to the casting rolls to keep the roll gap S at the target roll gap S. target , prestress F0=1.2×F upset In some optional embodiments, the movable casting roll bearing seat of a pair of casting rolls is pressed against the fixed casting roll bearing seat to apply a prestress F0 to the casting rolls so that the roll gap of the casting rolls is maintained at the target roll gap and does not change with the change of the casting and rolling force during the pouring process.

[0087] In step S3, if Figure 2 As shown in the figure, the control logic of the first closed-loop control circuit related to the casting flow Q is: according to the molten pool liquid level L and the set value L set The casting flow rate Q is adjusted based on the comparison result. Specifically, when the molten pool liquid level L is less than the set value L set When the casting flow rate is increased, the casting flow rate Q = Q0 + ΔQ; when the molten pool liquid level L is greater than the set value L set When the casting flow rate is reduced, the casting flow rate Q = Q0-ΔQ. The first closed-loop control circuit is used to control the molten pool liquid level L to be stable at L set Within ±2mm.

[0088] In step S3, if Figure 2 , Figure 3 The second closed-loop control loop shown is based on the actual casting force F actual and roller surface speed V actualAs a closed-loop response control loop composed of variables, the control logic of the second closed-loop control loop is: according to the actual casting force F actual With the set value F set The actual casting force F is adjusted based on the comparison results actual Specifically, when the actual casting force F actual Greater than the set value F set When the roller surface speed increases, the roller surface speed V actual+1 =V actual +ΔV; when the actual casting force F actual Less than the set value F set When the roller surface speed is reduced, the roller surface speed V actual+1 =V actual -ΔV. The actual casting force F is controlled by the second closed-loop control circuit actual Stable at (F upset , F downset ) interval, F upset is the maximum casting force of the twin-roll caster, F downset The minimum casting force required to ensure that the outlet cast strip hangs naturally without breaking.

[0089] The present invention also provides a twin-roller thin strip continuous casting start-up control system, the control system comprises a calculation module, a control module and a detection module.

[0090] The pre-calculation module is used to calculate the continuous casting parameters during the pouring process. It calculates the continuous casting parameters during the pouring process based on the following model. The continuous casting parameters at least include the upper limit of the casting force F upset , lower limit of casting force F downset , target roll gap S target , initial roller surface speed V0.

[0091] The monitoring module is used to monitor the molten pool liquid level L and the actual casting force F in real time during the casting process. actual .

[0092] The control module sets the continuous casting parameters according to the calculation results of the pre-calculation module and controls the continuous casting parameters during the pouring process; further, the control module includes a first control module, a second control module and a third control module.

[0093] The first control module is used to control the casting flow rate Q so that the molten pool liquid level L is stable within the target range; the second control module is used to control the roller surface speed V actual , so that the actual casting force F actual The third control module is used to apply a prestress F0 to the casting rolls so that the roll gap S is maintained at the target roll gap S. target .

[0094] When casting starts, the first control module controls the casting flow rate to Q0, and the second control module controls the roller surface speed of the casting roller to V0. Q0 is greater than the casting flow rate Q during stable production. actual When the monitoring module measures the molten pool liquid level L and reaches the set value L set After that, the first control module controls the molten pool liquid level L to be stable at L through the first closed-loop control circuit related to the casting flow Q. set ±2mm, the second control module controls the actual casting force F through a second closed-loop control loop related to at most two continuous casting parameters. actual Stable at (F upset , F downset ) interval, F upset is the maximum casting force of the twin-roll caster, F downset The minimum casting force required to ensure that the outlet cast strip hangs naturally without breaking.

[0095] The upper limit of the casting force F is calculated using the following formula: upset , lower limit of casting force F downset :

[0096]

[0097] Where, F is the casting force, kN; K is the deformation resistance, MPa; n σ is the stress state coefficient; B is the width of the casting strip, mm; R is the radius of the casting roll, mm; Δh is the reduction, mm;

[0098] The casting force F corresponding to the minimum Δh is F downset , the casting force F corresponding to the maximum Δh is F upset ;

[0099] The target roll gap S is calculated using the following formula: target :

[0100]

[0101] Where, S0 is the frame constant, mm; M is the casting machine stiffness, kN / mm; F actual is the actual casting force, kN;

[0102] The initial roll surface speed V0 is obtained by looking up a table, and different casting thicknesses correspond to different initial speeds.

[0103] The following formula is used to calculate the casting flow rate Q during stable production: actual :

[0104] Q actual =V0×h×B×ρ

[0105] Where V0 is the initial roller surface speed, m / min; h is the casting strip thickness, mm; B is the casting strip width, mm; ρ is the casting strip density, kg / m 3 ;

[0106] The casting flow rate at the beginning of casting is Q0 = 1.5 × Q actual .

[0107] Furthermore, the control logic of the first closed-loop control loop is: when the molten pool liquid level L is less than the set value L set When the casting flow rate is increased, the casting flow rate Q = Q0 + ΔQ; when the molten pool liquid level L is greater than the set value L set When the casting flow rate is reduced, the casting flow rate Q = Q0-ΔQ;

[0108] The second closed-loop control loop is based on the actual casting force F actual and roller surface speed V actual As a closed-loop response control loop composed of variables, the control logic of the second closed-loop control loop is: when the actual casting force F actual Greater than the set value F set When the roller surface speed increases, the roller surface speed V actual+1 =V actual +ΔV; when the actual casting force F actual Less than the set value F set When the roller surface speed is reduced, the roller surface speed V actual+1 =V actual -ΔV.

[0109] In some optional embodiments, the first control module adjusts the casting flow Q through a front-end flow control valve of the molten pool liquid level.

[0110] In some optional embodiments, the third control mold drives the movable casting roll bearing seat in a pair of casting rolls to press against the fixed casting roll bearing seat, thereby applying a prestress F0 to the casting roll, and the prestress F0=1.2×F upset , so that the roll gap S is maintained at the target roll gap S target .

[0111] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A twin-roller thin strip continuous casting method, characterized in that: The following steps are involved: Set the continuous casting parameters during the pouring process. The continuous casting parameters at least include the upper limit of the casting force F. upset , lower limit of casting force F downset , target roll gap S target , initial roller surface speed V0; Start casting and keep the roll gap S at the target roll gap S target , real-time monitoring of the molten pool liquid level L and the actual casting force F actual ; When the molten pool liquid level L reaches the set value L set After that, the first closed-loop control loop related to the casting flow Q is used to control the molten pool liquid level L to be stable within the target range, and the second closed-loop control loop related to at most two continuous casting parameters is used to control the actual casting force F. actual Stable within the target range.

2. The twin-roller thin strip continuous casting method according to claim 1, characterized in that: The upper limit of the casting force F is calculated using the following formula: upset , lower limit of casting force F downset : Where, F is the casting force, kN; K is the deformation resistance, MPa; n σ is the stress state coefficient; B is the width of the casting strip, mm; R is the radius of the casting roll, mm; Δh is the reduction, mm; The casting force F corresponding to the minimum Δh is F downset , the casting force F corresponding to the maximum Δh is F upset ; The target roll gap S is calculated using the following formula: target : Where, S0 is the frame constant, mm; M is the casting machine stiffness, kN / mm; F actual is the actual casting force, kN; The initial roll surface speed V0 is obtained by looking up a table, and different casting thicknesses correspond to different initial speeds.

3. The twin-roller thin strip continuous casting method according to claim 1, characterized in that: The casting flow rate at the beginning of casting is Q0, and the initial roller surface speed of the casting roller is V0; among them, Q0 is greater than the casting flow rate Q during stable production. actual .

4. The twin-roller thin strip continuous casting method according to claim 3, characterized in that: The following formula is used to calculate the casting flow rate Q during stable production: actual : Q actual =V0×h×B×ρ Where V0 is the initial roller surface speed, m / min; h is the casting strip thickness, mm; B is the casting strip width, mm; ρ is the casting strip density, kg / m 3 ; The casting flow rate at the beginning of casting is Q0 = 1.5 × Q actual .

5. The twin-roller thin strip continuous casting method according to claim 2, characterized in that: Before pouring, a prestress F0 is applied to the casting rolls to keep the roll gap S at the target roll gap S. target ; Among them, prestress F0 = 1.2 × F upset .

6. The twin-roller thin strip continuous casting method according to claim 5, characterized in that: A prestress F0 is applied to the casting rolls to keep the roll gap at a target roll gap by pressing the movable casting roll bearing seat of a pair of casting rolls against the fixed casting roll bearing seat.

7. The twin-roller thin strip continuous casting method according to claim 1, characterized in that: The control logic of the first closed-loop control loop related to the casting flow Q is: When the molten pool liquid level L is less than the set value L set When the casting flow rate is increased, the casting flow rate Q = Q0 + ΔQ; When the molten pool liquid level L is greater than the set value L set When , the casting flow rate is reduced, and the casting flow rate Q = Q0-ΔQ.

8. The twin-roller thin strip continuous casting method according to claim 7, characterized in that: The first closed-loop control loop related to the casting flow Q controls the molten pool liquid level L to be stable at L set Within ±2mm.

9. The twin-roller thin strip continuous casting method according to claim 1, characterized in that: The second closed-loop control loop is based on the actual casting force F actual and roller surface speed V actual As a closed-loop response control loop composed of variables.

10. The twin-roller thin strip continuous casting method according to claim 9, characterized in that: The actual casting force F actual and roller surface speed V actual The control logic of the relevant second closed-loop control loop is: When the actual casting force F actual Greater than the set value F set When the roller surface speed increases, the roller surface speed V actual+1 =V actual +ΔV; When the actual casting force F actual Less than the set value F set When the roller surface speed is reduced, the roller surface speed V actual+1 =V actual -ΔV.

11. The twin-roller thin strip continuous casting method according to claim 1, characterized in that: Actual casting force F actual The target interval is (F upset , F downset ), F upset is the maximum casting force of the twin-roll caster, F downset The minimum casting force required to ensure that the outlet cast strip hangs naturally without breaking.

12. A twin-roller thin strip continuous casting start-up control system, characterized in that: include: Pre-calculation module, used to calculate the continuous casting parameters during the pouring process, the continuous casting parameters at least include the upper limit of the casting force F upset , lower limit of casting force F downset , target roll gap S target , initial roller surface speed V0; A control module, which sets continuous casting parameters based on the calculation results of the pre-calculation module and controls the continuous casting parameters during the pouring process; Monitoring module, real-time monitoring of the molten pool liquid level L and actual casting force F during the casting process actual ; The control module includes: The first control module is used to control the casting flow Q actual , so that the molten pool liquid level L is stabilized within the target range; The second control module is used to control the roller surface speed V actual , so that the actual casting force F actual Stable within the target range.

13. The twin-roller thin strip continuous casting control system according to claim 12, characterized in that: The control module further includes a third control module, which is used to keep the roll gap S at the target roll gap S. target The third control mold drives the movable casting roll bearing seat in a pair of casting rolls to press against the fixed casting roll bearing seat, thereby applying a prestress F0 to the casting rolls to keep the roll gap S at the target roll gap S. target .

14. The twin-roller thin strip continuous casting pouring control system according to claim 12, characterized in that: When casting starts, the first control module controls the casting flow rate to Q0, and the second control module controls the roller surface speed of the casting roller to V0; wherein Q0 is greater than the casting flow rate Q during stable production. actual ; When the monitoring module measures the molten pool liquid level L reaches the set value L set After that, the first control module controls the molten pool liquid level L to be stable within the target range through the first closed-loop control circuit related to the casting flow rate Q, and the second control module controls the actual casting force F through the second closed-loop control circuit related to at most two continuous casting parameters. actual Stable within the target range.

15. The twin-roller thin strip continuous casting control system according to claim 14, characterized in that: The control logic of the first closed-loop control loop is: When the molten pool liquid level L is less than the set value L set When the casting flow rate is increased, the casting flow rate Q = Q0 + ΔQ; When the molten pool liquid level L is greater than the set value L set When the casting flow rate is reduced, the casting flow rate Q = Q0-ΔQ; The first closed-loop control loop related to the casting flow Q controls the molten pool liquid level L to be stable at L set Within ±2mm.

16. The twin-roller thin strip continuous casting control system according to claim 14, characterized in that: The second closed-loop control loop is based on the actual casting force F actual and roller surface speed V actual As a closed-loop response control loop composed of variables, the control logic of the second closed-loop control loop is: When the actual casting force F actual Greater than the set value F set When the roller surface speed increases, the roller surface speed V actual+1 =V actual +ΔV; When the actual casting force F actual Less than the set value F set When the roller surface speed is reduced, the roller surface speed V actual+1 =V actual -ΔV; Actual casting force F actual The target interval is (F upset , F downset ), F upset is the maximum casting force of the twin-roll caster, F downset The minimum casting force required to ensure that the outlet cast strip hangs naturally without breaking.

Images