A synergistic control method for fish tail defects at the tail end of a hot-rolled plate

Abstract

The application discloses a kind of synergic control methods of hot-rolled plate tail fish tail defects, belong to the technical field of steel rolling process, comprising: S1, flying shear triplet shearing shaping control: in the tail section of strip steel cutting stage, by the pre swing control of flying shear, shearing speed matching control and delay closing control, the cross section shape of strip steel tail section is actively shaped;S2, three-stage variable tension gradient coupling coiling control: in the preset length range before the tail section of strip steel enters coiler, establish segmented tension control model, constant tension, nonlinear slow descent tension and pulse disturbance tension are sequentially applied, and the tail section metal flow is intervened by coupling coiling drum speed control;S3, pinch roll three-dimensional synergic tail locking control: by the ovality control of pinch roll, negative speed difference control and cooling control, the multi-field coupling mechanism of geometry-speed-temperature is established, and the tail section of strip steel is locked.The application eliminates fish tail defect systematically from shearing, coiling, tail locking three links.

Description

Technical Field

[0001] This invention belongs to the technical field of steel rolling processes, and in particular relates to a collaborative control method for fishtail defects at the tail end of hot-rolled steel coils. Background Technology

[0002] During the coiling process of hot-rolled steel coils, the tail end of the strip is prone to quality defects such as fishtail opening, upward curling, and flaring due to sudden tension changes, uneven temperature gradients, and shear forces. Fishtail opening causes uneven strip end faces, affecting subsequent uncoiling and yield; upward curling causes uneven coil end faces, increasing transportation and storage risks; and flaring causes abnormal expansion of the head width, seriously affecting the stamping and welding quality of downstream users.

[0003] Existing technologies, both domestically and internationally, primarily employ constant tension or two-stage (constant + linear descent) tension models for tail winding tension control, lacking proactive intervention methods for the microscopic flow behavior of the tail metal. Pinch roll control often relies on single ellipticity compensation or simple speed difference control, failing to establish a multi-field coupling mechanism involving geometry, speed, and temperature. Flying shear control focuses primarily on shearing accuracy itself, lacking a systematic design for actively shaping the tail cross-sectional shape. The combination of these individual methods cannot fundamentally solve all three types of tail defects simultaneously, and there is currently no domestic or internationally available technical solution that systematically integrates pulsed perturbation tension, three-dimensional collaborative tail locking, and triple shearing shaping.

[0004] Therefore, there is an urgent need to develop a comprehensive control method for tail quality defects that combines multiple technologies and physical quantities, systematically eliminating fish tail defects from the three stages of shearing, winding, and tail locking. Summary of the Invention

[0005] To address the above-mentioned technical deficiencies, this invention provides a collaborative control method for fishtail defects at the tail of hot-rolled coils. By integrating a system of flying shear pre-swing-delay-variable speed triple shearing and tail shape active shaping technology, stepped-slope-pulse three-segment variable tension gradient coupled winding technology, and pinch roll ellipticity-speed difference-cooling three-dimensional collaborative tail locking technology, the fishtail defect is fundamentally eliminated.

[0006] To achieve the above-mentioned technical objectives, the present invention is implemented through the following technical solution: A collaborative control method for fishtail defects at the tail of hot-rolled steel coils includes: S1. Flying shear triple shearing shaping control: During the strip tail shearing stage, the cross-sectional shape of the strip tail is actively shaped through the flying shear's pre-swing control, shearing speed matching control, and delayed closing control. S2. Three-segment variable tension gradient coupled winding control: Within a preset length range before the tail of the strip enters the winding machine, a segmented tension control model is established, and constant tension, nonlinear slow-fall tension and pulse disturbance tension are applied in sequence, coupled with drum speed control, to intervene in the metal flow at the tail. S3. Three-dimensional collaborative tail-locking control of pinch rolls: By controlling the ellipticity of the pinch rolls, the negative speed difference control, and the cooling control, a multi-field coupling mechanism of geometry-speed-temperature is established to lock the tail of the strip.

[0007] Preferably, the pre-swing control specifically includes: the pre-swing angle of the flying shear is 10° to 15°, and the pre-swing start advance is 0.67s; The shearing speed matching control specifically involves controlling the shear exit speed V at the instant of shearing. 出 With strip speed V 带 Satisfy: V 出 - V 带 ≤ 0.20m / s; The delayed closing control specifically means that after the cutting is completed, the flying shear jaws maintain a delayed closing time of 0.2s.

[0008] Preferably, the shear rate matching control includes: generating a downward shear rate component during the control process, causing the tail section to form a natural downsloping angle α, where α = arcsin((V 出 - V 带 ) / V 带 ).

[0009] Preferably, the preset length range is the last 8.7m of the strip tail.

[0010] Preferably, the three control sections include: The first section, from the tail section to 5.2m, uses constant tension control with a tension coefficient K1=0.387. The second section, from 5.2m to 2.1m at the tail, employs nonlinear descent tension control, with the tension coefficient linearly decreasing from 0.387 to 0.215 at a slope of 0.043m / m. The third section, from the tail end to the roll tail, is subjected to a sinusoidal pulse tension disturbance with a pulse frequency of f=0.68Hz and an amplitude of ΔT=±3.2kN. Simultaneously, the pinch roll load coefficient K is controlled. 夹 =0.73, and the drum speed was gradually reduced from 14.7 rpm to 11.3 rpm.

[0011] Preferably, the tension coefficient K is defined as: K = T / (σ s × b × t), where T is the winding tension, σ s t is the strip yield strength, b is the strip width, and t is the strip thickness.

[0012] Preferably, the ellipticity control specifically involves controlling the ellipticity of the pinch roller to be ≤23.6μm.

[0013] Preferably, the negative speed difference control specifically involves: establishing the linear speed V of the pinch roller. 夹 With the linear velocity V of the drum surface 卷 Negative speed difference control window, ΔV = V 夹 - V 卷 = -0.17m / s ~ -0.09m / s.

[0014] Preferably, the cooling control includes controlling the single cooling time of the pinch roller to be 37.4s.

[0015] Preferably, the cooling control includes a cooling water flow rate of 18.7 L / min.

[0016] The advantages and technical effects of this invention are: This invention utilizes a three-stage shearing process involving pre-swing, delay, and variable speed, along with an active tail shape shaping technique. By using the shearing speed component to form a natural downward angle and by using jaw delay compression to shrink the width of the tail head, the upward tilt and flared mouth effect are geometrically eliminated.

[0017] This invention employs a three-stage variable tension gradient coupling winding technology (step-slope-pulse) to apply a specific tension model at different stages of the tail. In particular, it utilizes micro-tension oscillations to smooth out residual stress concentration in the dead zone of metal flow at the tail, and, in conjunction with drum deceleration, fundamentally eliminates the fish tail opening angle.

[0018] This invention utilizes a three-dimensional coordinated tail-locking technology based on the ellipticity of the pinch roller, speed difference, and cooling. By employing high-precision roller shape compensation, the reverse torque of the pre-bending angle generated by the negative speed difference, and stable temperature field control, it effectively suppresses the upward curling and geometric deviation of the fish tail.

[0019] This invention integrates the three processes of shearing, winding, and tail locking, achieving multi-technology synergy and multi-physical quantity coupling. It fundamentally solves three types of defects simultaneously: open tail, upturned tail, and flared tail, significantly improving the tail quality of hot-rolled coils. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A flowchart of a preferred embodiment of the present invention is shown. Detailed Implementation

[0022] To make the above-mentioned objectives, control system design, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0023] Please see Figure 1 A collaborative control method for fishtail defects at the tail of hot-rolled steel coils, comprising: S1. Flying shear triple shearing shaping control: During the strip tail shearing stage, the cross-sectional shape of the strip tail is actively shaped through the flying shear's pre-swing control, shearing speed matching control, and delayed closing control. S2. Three-segment variable tension gradient coupled winding control: Within a preset length range before the tail of the strip enters the winding machine, a segmented tension control model is established, and constant tension, nonlinear slow-fall tension and pulse disturbance tension are applied in sequence, coupled with drum speed control, to intervene in the metal flow at the tail. S3. Three-dimensional collaborative tail-locking control of pinch rolls: By controlling the ellipticity of the pinch rolls, the negative speed difference control, and the cooling control, a multi-field coupling mechanism of geometry-speed-temperature is established to lock the tail of the strip.

[0024] To better understand the technical solution of this invention, the following non-limiting explanation is provided: Pre-swing control: The pre-swing angle of the flying shear is 10° to 15°, and the pre-swing start advance is 0.67s, so that the flying shear has completed 80% of the stroke preparation before the strip arrives, ensuring the speed matching accuracy at the moment of shearing.

[0025] At the moment of shearing, the exit velocity of the flying shear and the strip velocity satisfy the relationship between the flying shear exit velocity V. 出 -Strip speed V 带 A velocity ≤0.20 m / s higher generates a downward shear velocity component, causing the tail section to form a natural downward slope, geometrically eliminating the upward slope tendency. Slope angle α = arcsin((V 出 - V 带 ) / V 带 ), where V 出 - V 带 ≤ 0.20m / s.

[0026] Delayed closing control: After shearing, the flying shear jaws maintain a delayed closing time of 0.2s, using the jaws to continuously squeeze the tail metal, causing the width of the tail end to shrink, thus suppressing the trumpet effect at its inception.

[0027] Within the last 8.7m of the strip tail, a segmented tension control model was established, dividing the tail winding process into three control segments: The first section (tail end 8.7m~5.2m, length 3.5m): constant tension control is adopted, with tension coefficient K1=0.387, to maintain the stable winding state of the strip tail metal and avoid end disturbance caused by sudden tension changes; The second section (5.2m to 2.1m, length 3.1m): adopts nonlinear slow tension control, the tension coefficient linearly slows down from 0.387 to 0.215 with a slope of 0.043m / m, so that the metal at the tail of the strip will undergo gradual compression deformation during the winding process, and gradually eliminate the dead zone of the metal flow at the tail. The third section (last 2.1m to the tail, length 2.1m): A sinusoidal pulse tension disturbance is applied, with a pulse frequency f=0.68Hz and an amplitude ΔT=±3.2kN, superimposed on the reference tension. The residual stress concentration in the dead zone of the tail metal flow is "smoothed out" by micro-tension oscillation. At the same time, the load factor of the pinch roller is reversed in this section to K_pinch=0.73 (far exceeding the conventional value of 0.5). In conjunction with the drum speed being reduced from 14.7rpm to 11.3rpm in a stepwise manner, the tail metal generates a pre-compression of 0.87mm in the last revolution, fundamentally eliminating the fishtail opening angle.

[0028] The tension coefficient K is defined as: K = T / (σ) s × b × t), where T is the winding tension, σ s t is the strip yield strength, b is the strip width, and t is the strip thickness.

[0029] The ellipticity control accuracy of the pinch roll is ≤23.6μm, and the geometric offset of the tail strip is eliminated by high-precision roll shape compensation; At the linear speed V of the pinch roller 夹 With the linear velocity V of the drum surface 卷 Establish a negative speed difference control window: ΔV = V 夹 - V 卷 = -0.17m / s ~ -0.09m / s, so that the tail strip generates a pre-bending angle of 1.7° at the moment of biting, and the reverse torque of the pre-bending angle effectively suppresses the fish tail from curling up.

[0030] The negative speed difference control window ensures that the pre-bending angle θ generated by the tail strip at the moment of bite satisfies: θ = arctan(|ΔV| / V 卷 ) ≈ 1.7°; where V_roll is the linear velocity of the roll surface.

[0031] The single cooling time of the pinch roll is extended from the conventional 25s to 37.4s, and the cooling water flow rate is set to 18.7L / min to ensure that the surface temperature gradient of the pinch roll is controlled within ≤4.3℃ / mm, so as to avoid the tail strip offset exceeding 0.15mm due to uneven thermal expansion.

[0032] If the temperature is still low or the suction is abnormal, a re-inspection should be conducted to determine if there is any residual blockage or damage to the ramp bricks.

[0033] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A collaborative control method for fishtail defects at the tail of hot-rolled steel coils, characterized in that, include: S1. Flying shear triple shearing shaping control: During the strip tail shearing stage, the cross-sectional shape of the strip tail is actively shaped through the flying shear's pre-swing control, shearing speed matching control, and delayed closing control. S2. Three-segment variable tension gradient coupled winding control: Within a preset length range before the tail of the strip enters the winding machine, a segmented tension control model is established, and constant tension, nonlinear slow-fall tension and pulse disturbance tension are applied in sequence, coupled with drum speed control, to intervene in the metal flow at the tail. S3. Three-dimensional collaborative tail-locking control of pinch rolls: By controlling the ellipticity of the pinch rolls, the negative speed difference control, and the cooling control, a multi-field coupling mechanism of geometry-speed-temperature is established to lock the tail of the strip.

2. The collaborative control method for fishtail defects at the tail end of hot-rolled coils according to claim 1, characterized in that, The pre-swing control specifically refers to the following: the pre-swing angle of the flying shear is 10° to 15°, and the pre-swing start advance is 0.67s; The shearing speed matching control specifically involves controlling the shear exit speed V at the instant of shearing. 出 With strip speed V 带 Satisfy: V 出 - V 带 ≤ 0.20m / s; The delayed closing control specifically means that after the cutting is completed, the flying shear jaws maintain a delayed closing time of 0.2s.

3. The collaborative control method for fishtail defects at the tail end of hot-rolled coils according to claim 2, characterized in that, The shear rate matching control includes: generating a downward shear rate component during the control process, causing the tail section to form a natural downsloping angle α, where α = arcsin((V 出 - V 带 ) / V 带 ).

4. The collaborative control method for fishtail defects at the tail of hot-rolled coils according to claim 1, characterized in that, The preset length range is the last 8.7m of the strip tail.

5. The collaborative control method for fishtail defects at the tail end of hot-rolled coils according to claim 4, characterized in that, The three control sections include: The first section, from the tail section to 5.2m, uses constant tension control with a tension coefficient K1=0.

387. The second section, from 5.2m to 2.1m at the tail, employs nonlinear descent tension control, with the tension coefficient linearly decreasing from 0.387 to 0.215 at a slope of 0.043m / m. The third section, from the tail end to the roll tail, is subjected to a sinusoidal pulse tension disturbance with a pulse frequency of f=0.68Hz and an amplitude of ΔT=±3.2kN. Simultaneously, the pinch roll load coefficient K is controlled. 夹 =0.73, and the drum speed was gradually reduced from 14.7 rpm to 11.3 rpm.

6. The collaborative control method for fishtail defects at the tail end of hot-rolled coils according to claim 5, characterized in that, The tension coefficient K is defined as: K = T / (σ s × b × t), where T is the winding tension, σ s t is the strip yield strength, b is the strip width, and t is the strip thickness.

7. The collaborative control method for fishtail defects at the tail of hot-rolled coils according to claim 1, characterized in that, The ellipticity control specifically refers to controlling the ellipticity of the pinch roller to be ≤23.6μm.

8. The collaborative control method for fishtail defects at the tail end of hot-rolled coils according to claim 7, characterized in that: The negative speed difference control specifically involves: establishing the linear speed V of the pinch roller. 夹 With the linear velocity V of the drum surface 卷 The negative speed difference control window between them, ΔV = V 夹 - V 卷 = -0.17m / s ~ -0.09m / s.

9. The collaborative control method for fishtail defects at the tail end of hot-rolled coils according to claim 8, characterized in that, The cooling control includes controlling the single cooling time of the pinch roller to be 37.4s.

10. The collaborative control method for fishtail defects at the tail of hot-rolled coils according to claim 9, characterized in that: The cooling control includes a cooling water flow rate of 18.7 L / min.

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