Position control method between hot finishing strip and guide mechanism

Abstract

This invention relates to a method for controlling the position of the strip and guide mechanism at the entrance of a hot finishing mill, belonging to the field of pre-rolling control technology for metal hot finishing mills. This method controls the second angle between the connecting line of the piston rod of the looper cylinder to the looper roller and the horizontal plane by periodically adjusting the looper cylinder. This allows the vertical contact position between the strip and the guide roller to be dynamically and periodically changing. Simultaneously, the guide mechanism is periodically adjusted to two different positions, high and low. This combination of the dynamic periodic changes in the strip position and the guide mechanism results in more dynamic changes in the vertical contact position between the strip and the guide roller, dispersing the wear points caused by concentrated vertical contact points, thereby significantly reducing wear.

Description

Technical Field

[0001] This invention relates to a position control method for the hot-rolled strip steel entry strip and guide mechanism, belonging to the field of pre-control technology for hot-rolled metal strip. Background Technology

[0002] The inlet of the finishing mill in a steel plant's hot rolling mill is equipped with a guide mechanism, which features inertial guide rollers. During use, the guide rollers may experience severe wear at the contact points because they make concentrated contact with the edge of the strip or along a specific line. Since the working angle of the looper remains constant, this wear can lead to a series of strip quality problems, including edge chipping, burrs, cracks, and waviness.

[0003] Existing technologies address the issue of foreign object intrusion into hot-rolled steel sheets by improving the guide structure and optimizing the guide ruler. For example, Chinese Patent Publication No. CN111451299 discloses a production method for reducing foreign object intrusion into the surface of hot-rolled sheets. This method involves replacing the liner plate of the finishing mill inlet guide with a double guide wheel and optimizing the guide ruler opening to reduce foreign object intrusion into the hot-rolled sheet surface. However, it does not mention guide wheel wear or guide wheel position control. Summary of the Invention

[0004] The technical problem to be solved by the present invention is: how to control and adjust the contact position between the strip and the guide wheel to reduce the contact wear between the strip and the guide wheel.

[0005] The technical solution proposed by the present invention to solve the above-mentioned technical problems is: a method for position control of the hot finishing mill entry strip and the guide mechanism, involving guide mechanisms arranged on both sides of the entry of the finishing mill and a looper roll arranged between two finishing mills, a guide cylinder is provided on one side of the guide mechanism, an eccentric device is provided below the guide mechanism, and a looper roll is provided with a looper cylinder.

[0006] Perform the following steps:

[0007] 1) When the first angle δ between the guide mechanism and the rolling horizontal plane is 0.5 degrees, it is in a high position; when the first angle δ between the guide mechanism and the rolling horizontal plane is 1.5 degrees, it is in a low position; and when the second angle β between the connecting line of the piston rod of the looper cylinder and the looper roll and the rolling horizontal plane is set, the guide mechanism is set in a high position by an eccentric device before the strip enters the finishing mill.

[0008] 2) Count the rolled strip Y according to the steel signal on the finishing mill stand;

[0009] 3) When Y≤5, the second included angle β is kept at 22 degrees by the movement of the looper cylinder, and the guide mechanism is kept in a high position;

[0010] 4) When 5 < Y ≤ 10, the second included angle β is made 23 degrees by the movement of the loop accumulator cylinder, and the guard mechanism remains at a high position;

[0011] 5) When 10 < Y ≤ 15, the second included angle β is made 24 degrees by the movement of the loop accumulator cylinder, and the guard mechanism remains at a high position;

[0012] 6) When 15 < Y ≤ 20, the second included angle β is made 25 degrees by the movement of the loop accumulator cylinder, and the guard mechanism remains at a high position;

[0013] 7) When 20 < Y ≤ 25, the second included angle β is made 26 degrees by the movement of the loop accumulator cylinder, and the guard mechanism remains at a high position;

[0014] 8) When 25 < Y ≤ 30, the second included angle β is made 26 degrees by the movement of the loop accumulator cylinder, and the guard mechanism is changed to a low position by the eccentric device;

[0015] 9) When the strip count Y > 30, the strip count Y is cleared to zero, the guard mechanism is set at a high position by the eccentric device, and steps 2) - 9) are repeated.

[0016] Furthermore, a speed sensor is provided on the guide wheel of the guard mechanism. When a speed signal is output by the speed sensor, the guard cylinder is controlled to stop so that the guard mechanism stops moving and locks its position.

[0017] The beneficial effects of the present invention are as follows: Since the second included angle between the connecting line of the piston rod of the loop accumulator cylinder connected to the loop roll and the horizontal plane is adjusted periodically (with 5 strips as a cycle) to control the loop accumulator cylinder, the loop roll can be in different positions dynamically and periodically in the vertical direction as the strip rolling process progresses (through the steel count), that is, the strip is in different positions dynamically and periodically in the vertical direction. Therefore, the position where the strip contacts the guide wheel of the guard mechanism in the vertical direction is in dynamic and periodic change; at the same time, the guard mechanism is adjusted periodically (with 30 strips as a cycle) to two different positions, high and low. Combining the dynamic and periodic change of the strip position with the dynamic and periodic change of the guard mechanism can make the position where the strip contacts the guide wheel in the vertical direction have more dynamic changes, thus dispersing the positions of wear caused by the contact between the strip and the guide wheel in the vertical direction, and greatly reducing the wear caused by the concentration of the contact positions between the strip and the guide wheel.

[0018] Furthermore, the pressure in the rodless cavity of the guard cylinder is controlled at 30 - 50 bar. Description of the Drawings

[0019] The following further describes the position control method of the hot rolling entry strip and the guard mechanism of the present invention in conjunction with the drawings.

[0020] Figure 1 This is a schematic diagram of the equipment structure at the hot finishing mill inlet.

[0021] Figure 2 yes Figure 1 Top view. Detailed Implementation

[0022] Example

[0023] The position control method for the hot finishing mill inlet strip and guide mechanism in this embodiment involves a certain hot finishing mill inlet device, such as... Figure 1 and Figure 2 As shown, taking finishing mills F1 and F2 of the finishing mill unit as an example, it includes a roll 1, strip 2, looper roll 3, guide mechanism 4, guide wheel 6, looper cylinder 7, eccentric device 8 and guide cylinder 10 located at the F2 inlet between finishing mills F1 and F2.

[0024] like Figure 1 and Figure 2 As shown, to accommodate roll systems with different roll diameters, the guide mechanism 4 is equipped with an eccentric device 8 at its lower part, with an eccentricity of 15mm. This allows control of the height position of the guide mechanism 4 within a range of 0-30mm. The corresponding first angle δ between the guide mechanism 4 and the rolling mill horizontal plane is controlled within a range of 0-2 degrees. This ensures smooth entry of the strip into the mill. The first angle δ is set by the eccentric device 8. In actual production, the first angle δ is generally set to two values: 0.5 degrees and 1.5 degrees. The corresponding absolute difference in elevation between the guide rollers is 20mm. Two guide rollers 6 are symmetrically installed on the guide mechanisms 4 on both sides of the finishing mill entrance.

[0025] like Figure 1 and Figure 2 As shown, the looper roll 3 is installed at the mill exit to facilitate the smooth passage of strip steel to the next mill. After passage, it is raised to a set position to create tension and prevent strip stacking. The movement of the looper roll 3 is controlled by a looper cylinder 7 installed on the drive side. An angle encoder 11 is installed on the side of the rolling line. The second included angle β between the piston rod of the looper cylinder 7 and the connecting line of the looper roll 3 and the rolling horizontal plane is fed back by the angle encoder 11. Before steel passage, the looper cylinder 7 is fully retracted, and the upper roll surface of the looper roll 3 is about 15mm below the rolling horizontal line. At this time, the angle encoder 11 feeds back the second included angle β as 0 degrees. During steel passage, the looper cylinder 7 controls the second included angle β within the range of 22-26 degrees.

[0026] The position control method for the hot-rolled steel inlet strip and the guide mechanism in this embodiment performs the following steps:

[0027] 1) Assume that when the first included angle δ between the guard rail mechanism 4 and the rolling horizontal plane is 0.5 degrees, it is in the high position, and when the first included angle δ between the guard rail mechanism 4 and the rolling horizontal plane is 1.5 degrees, it is in the low position. Assume the second included angle β between the connecting line of the piston rod of the loop accumulator cylinder 7 and the loop accumulator roll 3 and the rolling horizontal plane. Before the strip steel 2 enters the entrance of the finishing mill, the guard rail mechanism 4 is set in the high position through the eccentric device 8;

[0028] 2) Count the strip steel 2 being rolled as Y according to the signal of the presence of steel in the finishing mill stand;

[0029] 3) When Y ≤ 5, make the second included angle β be 22 degrees through the movement of the loop accumulator cylinder 7, and the guard rail mechanism 4 remains in the high position;

[0030] 4) When 5 < Y ≤ 10, make the second included angle β be 23 degrees through the movement of the loop accumulator cylinder, and the guard rail mechanism 4 remains in the high position;

[0031] 5) When 10 < Y ≤ 15, make the second included angle β be 24 degrees through the movement of the loop accumulator cylinder, and the guard rail mechanism 4 remains in the high position;

[0032] 6) When 15 < Y ≤ 20, make the second included angle β be 25 degrees through the movement of the loop accumulator cylinder, and the guard rail mechanism 4 remains in the high position;

[0033] 7) When 20 < Y ≤ 25, make the second included angle β be 26 degrees through the movement of the loop accumulator cylinder, and the guard rail mechanism 4 remains in the high position;

[0034] 8) When 25 < Y ≤ 30, make the second included angle β be 26 degrees through the movement of the loop accumulator cylinder, and change the guard rail mechanism 4 to the low position through the eccentric device, that is, make the first included angle δ = 1.5 degrees;

[0035] 9) When the count of the strip steel Y > 30, clear the count of the strip steel 2 as Y, set the guard rail mechanism in the high position through the eccentric device, and repeat steps 2) - 9).

[0036] A further change in this embodiment is: A speed sensor 5 is provided on the guide wheel 6 of the guard rail mechanism 4. The guide wheel 6 has no drive and will only rotate when it touches the strip steel 2, and its rotation speed is fed back by the speed sensor 5. The opening degrees between the two guard rail mechanisms 4 and their two guide wheels 6 are respectively controlled and fed back by two guard rail cylinders 10 and displacement sensors 9 provided on the guard rail cylinders 10. When the speed sensor outputs a speed signal, control the guard rail cylinder to stop so that the guard rail mechanism stops moving and locks the position.

[0037] In this embodiment, the strip width L = 1200mm. When the finishing mill F2 bites the strip, the two guide cylinders 10 on both sides close at a set speed. Theoretically, the two guide wheels 6 on both sides should contact the strip 2 simultaneously. The feedback speeds of the two guide wheels 6 are v1 and v2, respectively, and the stroke feedback of the two guide cylinders 10 is 600mm. However, in reality, the center line of the strip may be off to one side, or the two guide wheels 6 on both sides may wear unevenly. Therefore, when the two guide cylinders 10 on both sides close at the set speed, the two guide wheels 6 may not necessarily contact the strip simultaneously. Therefore, when the guide wheel 6 on the drive side has a feedback value of v1, the guide cylinder 10 on the drive side should be stopped immediately and locked in position; similarly, when the guide wheel 6 on the working side has a feedback value of v2, the guide cylinder 10 on the working side should be stopped immediately and locked in position.

[0038] This embodiment describes the equipment (loop rolls and guide mechanisms, etc.) between finishing mills F1 and F2. The method described in this embodiment is also applicable to other finishing mills such as F2-F3.

[0039] Furthermore, to prevent damage to the guide wheel 6 caused by tail swing or to prevent over-operation of the guide cylinder 10 due to mechanical jamming and lack of speed signals v1 and v2 feedback when the guide wheel 6 does not rotate, a protection program is set to control the rodless chamber pressure of the guide cylinder within a certain range. The specific value needs to be set according to the thickness of the front frame strip, the effective area of ​​the guide cylinder, the strip temperature, and the steel grade. In this embodiment, the strip thickness of F1 is 20mm, and the rodless chamber pressure of the F2 inlet guide cylinder 10 is set to 50bar. If it is the F3 inlet guide cylinder 10 rodless chamber pressure, it is set to 45bar; if it is the F4 inlet guide cylinder 10 rodless chamber pressure, it is set to 40bar; if it is the F5 inlet guide cylinder 10 rodless chamber pressure, it is set to 35bar; and if it is the F6 inlet guide cylinder 10 rodless chamber pressure, it is set to 30bar.

[0040] The above description is only a preferred embodiment of the present invention, but the present invention is not limited thereto. All equivalent substitutions or modifications made to the concepts and technical solutions of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for controlling the position of a hot finishing entry strip and guide mechanism, involving a guide mechanism arranged on both sides of the entry of a finishing mill and a loop roller arranged between two finishing mills, one side of the guide mechanism being provided with a guide oil cylinder, the lower side of the guide mechanism being provided with an eccentric device, and the loop roller being provided with a loop oil cylinder, characterized in that Perform the following steps: 1) Assume that when the first included angle δ between the guard rail mechanism and the rolling horizontal plane is 0.5 degrees, it is in the high position, and when the first included angle δ between the guard rail mechanism and the rolling horizontal plane is 1.5 degrees, it is in the low position. Assume the second included angle β between the connecting line of the piston rod of the loop accumulator cylinder and the loop accumulator roll and the rolling horizontal plane. Before the strip enters the entrance of the finishing mill, set the guard rail mechanism in the high position through the eccentric device; 2) Count the rolled strip Y according to the signal indicating the presence of steel in the finishing mill stand; 3) When Y ≤ 5, move the loop accumulator cylinder to make the second included angle β 22 degrees, and the guard rail mechanism remains in the high position; 4) When 5 < Y ≤ 10, move the loop accumulator cylinder to make the second included angle β 23 degrees, and the guard rail mechanism remains in the high position; 5) When 10 < Y ≤ 15, move the loop accumulator cylinder to make the second included angle β 24 degrees, and the guard rail mechanism remains in the high position; 6) When 15 < Y ≤ 20, move the loop accumulator cylinder to make the second included angle β 25 degrees, and the guard rail mechanism remains in the high position; 7) When 20 < Y ≤ 25, move the loop accumulator cylinder to make the second included angle β 26 degrees, and the guard rail mechanism remains in the high position; 8) When 25 < Y ≤ 30, move the loop accumulator cylinder to make the second included angle β 26 degrees, and change the guard rail mechanism to the low position through the eccentric device; 9) When the strip count Y > 30, clear the strip count Y, set the guard rail mechanism in the high position through the eccentric device, and repeat steps 2) - 9); 2. The position control method for the hot-rolled strip entrance and guide mechanism according to claim 1, characterized in that: A speed sensor is provided on the guide wheel of the guard rail mechanism. When the speed sensor outputs a speed signal, control the guard rail cylinder to stop so that the guard rail mechanism stops moving and locks its position.

3. The position control method for the hot-rolled strip entrance and guide mechanism according to claim 1, characterized in that: The pressure in the rodless cavity of the guard rail cylinder is controlled at 30 - 50 bar.

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