Method for manual intervention in the event of an on-line thickness anomaly in a plate mill

Abstract

This invention discloses a method for manual intervention in online thickness anomalies of medium-thick plate hot rolling mills. The method includes: after the primary system of the hot rolling mill receives relevant parameters sent by the secondary system, the electric pressing system EGC's pressing screw (11), driven by the pressing motor (12), adjusts the roll gap of the upper and lower rolls (3) from large to small to the current rolling roll gap position; the hydraulic AGC cylinder (1) is raised, pushing the lower support roll (2) and the lower roll to the rolling line position; the roller table (4) transports the rolled piece (7) for reciprocating rolling in the hot rolling mill; the head of the finished product pass is measured and fed back by a thickness gauge (5); based on the feedback thickness, the operator manually intervenes in the thickness using the gap+ / gap- buttons in the lower left corner of the mill's main screen, combining real-time measurement feedback from the thickness gauge (5) for manual intervention optimization. The advantage of this invention is that it allows for quick and safe manual thickness intervention through newly added function buttons on the operating interface, improving product qualification rate.

Description

Technical Field

[0001] This invention belongs to the fields of steel metallurgical equipment control technology and production safety technology, and particularly relates to a method for manual intervention in online thickness anomalies of medium and heavy plate hot rolling mills. Background Technology

[0002] The medium-thick plate hot roll mill production line consists of a four-high mill, two coiling furnaces before and after the mill, and subsequent thickness gauges, flying shears, and laminar flow cooling systems. The hot roll mill production line has four production modes: flat-rolled plates, flat-rolled coils, coiled plates, and coiled coils, with the appropriate mode selected based on the production plan. After being heated in the furnace, the rolled product passes through a descaling system to remove surface iron oxide scale, and is then transported via roller conveyors to the hot roll mill area. Through multiple rolling passes, the final finished product thickness and length are achieved. The product is then sheared into mother plates by a flying shear before proceeding to subsequent processes. Flat-rolled plates or coils have a finished product length of 15–92 m and a billet weight of 14–42 t; coiled plates or coils have a length of 80–340 m and a billet weight of 20–67 t.

[0003] Regarding thickness control, current rolling mill thickness control methods involve the electric or hydraulic pressing system activating to a given roll gap size under no-load conditions, after which the mill begins to bite into the workpiece for rolling. Under load, the roll gap stops moving to ensure thickness stability. The main methods currently include: a secondary system performs simulation calculations, then sends parameters to the primary system, which controls the specific actions of the equipment. This involves adjusting the roll gap size for each pass of the hot rolling mill through the pressing system to ensure the final finished product thickness. Currently, the mainstream thickness control methods for medium and heavy plate production lines are: 1. Real-time thickness measurement by a thickness gauge in odd / even precision rolling passes, forming a closed-loop control with the mill thickness control; 2. The thickness gauge only detects and provides feedback on the thickness, but this is not a closed-loop control with the mill thickness control. Of the above methods, Method 1 is suitable for hot continuous rolling production lines and production lines with less dense on-site equipment. For hot rolling coil production lines with dense on-site equipment and a humid and hot working environment, the thickness gauge is affected by factors such as the high temperature of the coiling furnace, frame vibration, flying shear, and cooling water near the rolling mill, resulting in a relatively large deviation in measurement accuracy. Therefore, it is not suitable for closed-loop thickness control of the rolling mill. Medium and heavy plate coil rolling mill production lines usually adopt the mainstream thickness control method 2, which moves the thickness gauge to a position a certain distance behind the rolling mill to participate in thickness detection and feedback.

[0004] Given the second mainstream thickness control method, production line operators typically adjust the thickness of the current rolled piece based on the thickness measurement of the previous rolled piece. Once the rolled piece enters the finishing pass, its thickness cannot be manually intervened; intervention is only possible before the finishing pass. If there is a significant deviation in the thickness control of the hot-rolled coil mill, and it is not properly corrected before the finishing pass, it can lead to the finishing pass thickness being too thick or too thin, resulting in an unplanned abnormal thickness of the entire rolled piece.

[0005] Abnormal thickness of the entire rolled piece can affect lengths of 20-340m and weights of 14-67t, resulting in significant losses for production companies. Such thickness anomalies occur frequently during daily production, accumulating and significantly impacting company profits over time. Therefore, a solution is needed to effectively and quickly mitigate the economic losses caused by thickness anomalies. Summary of the Invention

[0006] The purpose of this invention is to solve the problem of economic losses caused by abnormal thickness of existing rolled parts. It provides a manual intervention method for online thickness abnormalities in medium and heavy plate hot rolling mills, which improves the original traditional thickness control method. When operators predict abnormal thickness during the finished product rolling pass, or when the thickness gauge shows abnormal thickness at the head of the rolled part, they can quickly and safely intervene manually through the newly added function buttons on the operation interface to assist in thickness control and improve the product qualification rate.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A method for manual intervention in online thickness anomalies of medium-thick plate hot rolling mills, comprising the following steps:

[0009] (1) After receiving the relevant parameters sent by the secondary system, the pressing screw of the electric pressing system EGC, driven by the pressing motor, adjusts the roll gap of the upper and lower rolls from large to small to the current rolling roll gap position.

[0010] (2) The hydraulic AGC cylinder is raised, pushing the lower support roll and the lower rolling roll to the rolling line position;

[0011] (3) The roller conveyor conveys the rolled pieces for reciprocating rolling in the hot rolling mill;

[0012] (4) The thickness d of the head of the finished rolled piece is measured by a thickness gauge;

[0013] (5) Based on the thickness of the rolled piece head as fed back by the thickness gauge, the operator manually intervenes in the thickness by pressing the gap+ / gap- button in the lower left corner of the main screen of the rolling mill, and optimizes the manual intervention by combining the real-time measurement feedback from the thickness gauge.

[0014] Furthermore, in steps (1) and (2), the upper and lower rolls are the upper working roll and the lower working roll of the furnace coil mill.

[0015] Furthermore, in step (4), the target thickness of the finished rolled piece is set as x, the lower limit of the thickness tolerance is +0.3mm, and the final thickness of the finished product should preferably be controlled within x±0.2mm.

[0016] Furthermore, in step (5), the hydraulic oil volume of the hydraulic AGC cylinder is controlled by manually intervening with the gap+ / gap- button, thereby converting it into the extension and retraction of the hydraulic AGC cylinder, and thus controlling the thickness.

[0017] Furthermore, in steps (4) and (5), if the thickness of the rolled piece head is lower than the lower limit of the rolled piece thickness after being measured by the thickness gauge, the thickness is increased by a multiple of 0.05 mm each time manual intervention is performed; if the thickness of the rolled piece head is higher than the upper limit of the rolled piece thickness after being measured by the thickness gauge, the thickness is decreased by a multiple of 0.05 mm each time manual intervention is performed.

[0018] In the technical solution of this invention, the roll gap compensation function of the hydraulic AGC cylinder is optimized based on the structure of the production equipment, and the original traditional thickness control method is improved. When the rolling mill is under rolling load, if the operator anticipates abnormal thickness during the finished product pass rolling, or if the thickness of the rolled piece head is abnormal as indicated by a thickness gauge, manual thickness intervention can be quickly and safely performed through the newly added gap+ / gap- buttons on the operation interface. The intervention method of this invention is stable, simple to operate, has a fast response speed, and high safety when the rolling mill is under rolling load, greatly reducing the amount of unplanned occurrences caused by abnormal thickness control of the hot-rolled coil mill, and reducing various economic losses caused by unplanned occurrences. Attached Figure Description

[0019] Figure 1 This is a schematic diagram showing the location of the thickness control unit component of the thick plate furnace coil rolling mill according to the present invention;

[0020] Figure 2 This is the main operation screen for the medium and heavy plate hot rolling mill of this invention;

[0021] Figure 3 A manual thickness intervention button has been added to the main operation screen of the medium and heavy plate hot rolling mill in this invention;

[0022] Figure 4 This is a schematic diagram showing the relative positions of various equipment in the heavy plate hot rolling mill production line of this invention. Detailed Implementation

[0023] Example

[0024] To make the present invention clearer, the following description, in conjunction with the accompanying drawings, further illustrates a method for manual intervention in online thickness anomalies of a medium-thick plate hot rolling mill. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0025] Taking a billet size of 150*2894*12000mm, a finished product size of 10*2894*180000mm, and 11 rolling passes as an example, see [link / reference]. Figure 1 and Figure 4 The equipment used includes a hydraulic AGC cylinder 1, a pressing screw 11, a pressing motor 12, a lower support roller 2, upper and lower rolls 3, an upper work roll 31 of the hot plate rolling mill, a lower work roll 32 of the hot plate rolling mill, a roller table 4, a thickness gauge 5, a flying shear 6, a rolled piece 7, and a hot plate rolling mill coiling furnace 8. A method for manual intervention in online thickness anomalies of a medium-thick plate hot plate rolling mill is described, with the following specific steps, characterized by:

[0026] (1) After receiving the relevant parameters sent by the secondary system, the pressing screw 11 of the electric pressing system EGC, driven by the pressing motor 12, adjusts the roll gap between the upper working roll 31 and the lower working roll 32 of the furnace rolling mill from large to small to the current roll gap position.

[0027] (2) The hydraulic AGC cylinder 1 is raised, pushing the lower support roll 2 and the lower working roll 32 of the furnace coil mill to the horizontal position of the rolling line;

[0028] (3) The roller conveyor conveys the rolled piece 7 to be reciprocated in the hot rolling mill;

[0029] (4) The thickness of the finished rolled piece 7 should be controlled within 10mm ± 0.2mm, that is, the upper limit of the tolerance is 10.2mm and the lower limit is 9.8mm. The thickness of the head 10 meters measured by the thickness gauge 5 is 9.65mm.

[0030] (5) Based on the thickness reading from the thickness gauge 5 and combined with past operational experience, it is judged that the thickness of the rolled piece 7 will fluctuate appropriately during subsequent rolling, which may easily lead to the thickness exceeding the lower limit of 9.8 mm. See [reference needed]. Figure 2 and Figure 3 The operator immediately intervened manually by adding 0.2mm to the thickness using the gap+ / gap- button in the lower left corner of the main screen of the hot rolling mill, ensuring that the subsequent rolling thickness of the workpiece 7 was 9.85mm. Combined with the real-time measurement feedback from the thickness gauge 5, further manual intervention was performed to optimize the thickness (that is, by manually intervening with the gap+ / gap- button to control the amount of hydraulic oil entering and leaving the hydraulic AGC cylinder 1, the amount of extension and retraction of the hydraulic AGC cylinder 1 was converted into thickness control), thereby ensuring that the thickness of the workpiece, except for the head 10 meters and the adjustment section 5 meters, was within the normal range.

[0031] After using the method of the present invention, the entire rolled piece is 180m long. Through the intervention of the manual intervention function, it can be ensured that the 165m rolled piece is a qualified product, effectively avoiding the risk that the thickness of the entire rolled piece exceeds the lower limit of 9.8mm.

[0032] This invention provides a manual intervention method that maximizes the compensation for deficiencies in control measures when the rolling mill experiences thickness control abnormalities. It offers operators a simple, effective, and rapid method for thickness compensation and recovery when the rolling mill is under rolling load. The invention is simple to operate and structure, easy to maintain, and significantly reduces the unplanned occurrence rate of rolled products due to thickness control abnormalities in hot-rolled coil mills, thereby improving the finished product qualification rate. It serves as a remedial measure for thickness control abnormalities in hot-rolled coil mills.

[0033] In addition to the embodiments described above, the present invention may have other implementations. All technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by the present invention.

Claims

1. A method for manual intervention in online thickness anomalies of medium-thick plate hot rolling mills, comprising the following specific steps, characterized in that: Step 1: After receiving the relevant parameters sent by the secondary system, the pressing screw (11) of the electric pressing system EGC, driven by the pressing motor (12), adjusts the roll gap of the upper and lower rolls (3) from large to small to the current rolling roll gap position. Step 2: The hydraulic AGC cylinder (1) is raised, pushing the lower support roller (2) and the lower rolling roller to the rolling line position; Step 3: The roller conveyor (4) transports the rolled piece (7) to the hot rolling mill for reciprocating rolling; Step 4: The head of the finished rolled piece is measured by a thickness gauge (5) to provide feedback on the thickness d; Step 5: Based on the thickness of the head of the rolled piece (7) as fed back by the thickness gauge (5), the operator controls the amount of hydraulic oil entering and exiting the hydraulic AGC cylinder (1) by using the gap+ / gap- button in the lower left corner of the main screen of the rolling mill. This is converted into the extension and retraction of the hydraulic AGC cylinder (1) to control the thickness. Combined with the real-time measurement feedback from the thickness gauge (5), manual intervention is carried out for optimization.

2. The method for manual intervention in online thickness anomalies of medium and heavy plate hot rolling mills according to claim 1, characterized in that: In steps one and two, the upper and lower rolls (3) are the upper working roll (31) and the lower working roll (32) of the furnace coil mill.

3. The method for manual intervention in online thickness anomalies of medium-thick plate hot rolling mills according to claim 1 or 2, characterized in that: In step four, the target thickness of the finished rolled piece is set as x, the lower limit of the thickness tolerance is +0.3mm, and the final thickness of the finished product should preferably be controlled within x±0.2mm.

4. The method for manual intervention in online thickness anomalies of medium and heavy plate hot rolling mills according to claim 3, characterized in that: In steps four and five, if the thickness of the head of the rolled piece (7) is lower than the lower limit of the thickness of the rolled piece after being measured by the thickness gauge (5), the thickness will be increased by a multiple of 0.05 mm each time manual intervention is performed. If the thickness of the head of the rolled piece (7) is higher than the upper limit of the thickness of the rolled piece after being measured by the thickness gauge (5), the thickness will be decreased by a multiple of 0.05 mm each time manual intervention is performed.

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