A control method and control system for rolling mill shutdown
By combining thickness gauge and encoder in the rolling mill shutdown control system, the thickness and length of steel plates are monitored in real time, the problem of inaccurate rolling mill shutdown in the existing technology is solved, the material utilization rate and safety are improved, and the accurate parking of the rolling mill is achieved .
Patent Information
- Application Number
- CN202010612475.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2020-06-30
- Publication Date
- 2024-12-24
- Estimated Expiration
- 2040-06-30
AI Technical Summary
The prior art cannot achieve accurate shutdown when rolling mills cold rolled steel strips, resulting in low safety factors and waste of materials.
The rolling mill shutdown control system is adopted, combined with thickness gauge and encoder, and the thickness and length of the steel plate are monitored in real time. The plate thickness control module is used to issue speed reduction and shutdown commands to the rolling mill to ensure that the rolling mill is stopped accurately when the predetermined thickness deviation is reached, and material utilization is improved. and security.
Accurate shutdown of the rolling mill is achieved, material utilization and safety factor are improved, and waste and accidents caused by excessive length of the plate tail or head.
Smart Images
Figure CN111729938B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of steel strip production equipment, and in particular to a rolling mill shutdown control method and a control system thereof. Background Art
[0002] When a reversible rolling mill is used to produce steel strips by cold rolling, all the main performance indicators meet the production needs after production, but there are some shortcomings in the control of the tail part of the rolled plate, and there is room for improvement. The reversible rolling mill performs multiple cold rolling on the steel strip to meet the use requirements. According to the prior art, a control system for the thickness of the rolled plate is disclosed on the website of the State Intellectual Property Office, with the announcement number CN106180207B. The steel plate is fed into the rolling mill for rolling, and the thickness of the steel plate before and after rolling is monitored in real time by a thickness gauge. When the thickness gauge measures that the real-time data of the thickness of the steel plate before rolling is more than 2% but less than 5% of the set data of the thickness before rolling, the rolling mill unit slows down production; when the thickness gauge measures that the real-time data of the thickness of the steel plate before rolling is 5% thicker than the set data of the thickness before rolling, the rolling mill unit stops. Only using a thickness gauge to test the thickness of the steel plate before rolling to slow down or stop the rolling mill unit cannot achieve accurate stopping. If the rolling line is crossed, an accident may occur, and the safety factor is low. If the calculated length is shorter than the actual length, the rolling mill may stop prematurely, wasting materials. Summary of the invention
[0003] The technical problem to be solved by the present invention is to overcome the defects of the above-mentioned prior art and provide a control method and a control system for a rolling mill shutdown with a high safety factor and no waste of materials.
[0004] In order to achieve the above object, the technical solution of the present invention is:
[0005] A control system for a rolling mill shutdown, comprising a rolling mill control unit, a main control unit, a plate thickness control module and an industrial control computer, wherein thickness gauges are provided at the outlet and the inlet of the work rolls, and the main control unit further comprises an encoder for detecting the length of the rolled plate, wherein the plate thickness control module is respectively connected to the encoder and the thickness gauge, wherein the plate thickness control module is mutually connected to the industrial control computer and exchanges data, wherein the plate thickness control module sends a speed reduction command to the rolling mill when the length of the work rolls from the rolling line reaches the remaining length, wherein the plate thickness control module sends a speed-unchanging or delayed shutdown command to the rolling mill when the set data of the target plate thickness to be rolled is compared with the real-time data obtained from the thickness gauge, wherein the main control unit is respectively connected to the plate thickness control module and the rolling mill control unit, and receives instructions from the plate thickness control module.
[0006] After adopting the above structure, the present invention has the following advantages compared with the prior art: adding a kind of precision control, using the encoder to detect the length of the rolled plate, when the working roller of the rolling mill reaches the remaining length from the previous rolling line, the rolling mill is decelerated until it is decelerated to 50m / min. When the rolling mill is decelerated to 50m / min, the length of the working roller from the previous rolling line is 10 meters. The thickness gauge detects that the thickness is 10% thicker (the rolling line of the previous rolling), and then the mill is stopped after a delay of 2 seconds. If the thickness gauge detects that the thickness is not 10% thicker, the rolling mill maintains a speed of 50m / min unchanged until the thickness gauge detects that the thickness is 10% thicker and then the mill is stopped after a delay of 2 seconds. In this way, the two adjacent rolling lines on the same side of the steel plate are only about 0.2 meters, which improves the utilization rate of materials, has a high safety factor, and does not waste materials.
[0007] Preferably, the rolling mill control unit includes a frequency converter and a motor, the frequency converter is connected to the motor, and the main control unit is connected to the frequency converter. The main control unit receives instructions from the plate thickness control module and controls the frequency converter to adjust the speed of the motor.
[0008] The encoders are respectively arranged on the guide roller and the plate-shaped roller. The lengths before and after rolling are different, and encoders need to be arranged on both the guide roller and the plate-shaped roller for detection.
[0009] The encoder is an Omron high-precision encoder with high precision.
[0010] The thickness gauge is an X-ray thickness gauge. X-rays are emitted from the X-ray thickness gauge. It is a non-contact thickness gauge that can adapt to the harsh environment of the steel rolling site and has high measurement accuracy. The X-ray thickness gauge is now combined with computers and automation technology.
[0011] The plate thickness control module stores the set data of plate thickness, and can compare the set data of the target plate thickness to be rolled with the real-time data obtained from the thickness gauge, thereby issuing a command to the rolling mill output to keep the speed constant or delay shutdown.
[0012] The plate thickness control module realizes its function through the plate thickness PLC.
[0013] When the real-time data of the thickness of the tail of the steel plate measured by the thickness gauge exceeds 10% of the set data of the thickness before rolling, the machine is stopped after a delay of two seconds.
[0014] Based on the above-mentioned control method of a rolling mill shutdown control system, it comprises the following steps:
[0015] 1. The steel coil is loaded on the entrance unwinder. After the steel coil is ready, the first rolling process begins: the entrance unwinder is started, the plate head of the steel coil is sent to the exit tension roller, the hydraulic cylinder is pushed upward to make the work roller press the steel plate, the rolling mill is started, the thickness gauge and the encoder are also started, the thickness gauge measures the thickness of the steel plate before and after rolling, and the encoder measures the length of the steel plate before and after rolling;
[0016] 2. The steel coil is rolled onto the exit tension roller. When the tail of the steel coil stops near the entrance tension roller, the rolling mill stops. The first rolling pass is completed. The head and tail of the steel coil form a rolling line. The tail of the steel coil passes through the entrance tension roller.
[0017] 3. Multiple rolling passes are carried out afterwards. The steel coil is wound back and forth between the exit tension roller and the entrance tension roller. The encoder is used to detect the length of the rolled plate. When the length of the work roller from the previous rolling line reaches the remaining length, a speed reduction command is issued to the rolling mill. When the length of the work roller from the previous rolling line is 10 meters (at this time the production line speed is reduced to 50m / min), the machine is stopped for two seconds when the real-time data of the steel plate thickness measured by the thickness gauge exceeds 10% of the set data of the thickness before rolling. When the real-time data of the steel plate thickness measured by the thickness gauge does not exceed 10% of the set data of the thickness before rolling, the speed remains unchanged.
[0018] Compared with the prior art, the present invention has the following advantages: the control method can be used to more accurately stop the rolling mill, and the encoder is used to detect the length of the rolled plate. When the working roller of the rolling mill reaches the remaining length from the previous rolling line, the rolling mill is decelerated until it is decelerated to 50m / min. When the rolling mill is decelerated to 50m / min, the length of the working roller from the previous rolling line is 10 meters. The thickness gauge detects that the thickness is 10% thicker (the rolling line of the previous rolling), and then the mill is stopped after a delay of 2 seconds. If the thickness gauge detects that the thickness does not reach 10% thicker, the rolling mill maintains a speed of 50m / min unchanged until the thickness gauge detects that the thickness is 10% thicker, and then the mill is stopped after a delay of 2 seconds. In this way, the two adjacent rolling lines on the same side of the steel plate are only about 0.2 meters, which improves the utilization rate of materials, has a high safety factor, and does not waste materials. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 It is a layout diagram of a rolling mill of a rolling mill shutdown control system of the present invention;
[0020] Figure 2 The invention discloses a circuit schematic diagram of a control system for stopping a rolling mill.
[0021] Among them, 1. rolling mill control unit, 2. main control unit, 3. plate thickness control module, 4. frequency converter, 5. encoder, 6. industrial computer, 7. motor, 101. entrance unwinder, 102. pressure roller, 103. telescopic guide plate, 104. leveling machine, 105. entrance tension roller, 106. CPC, 107. wedge block, 108. back roller, 109. working roller, 110. push-up hydraulic cylinder, 111. exit tension roller, 112. pressure roller, 206. thickness gauge, 207. plate shape roller. DETAILED DESCRIPTION
[0022] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.
[0023] like Figure 1 and 2 As shown, the present invention provides a control system for a rolling mill shutdown, comprising a rolling mill control unit 1, a main control unit 2, a plate thickness control module 3 and an industrial control computer 6, wherein the outlet and the inlet of the work roll 109 are both provided with a thickness gauge 206, and the plate thickness control module 3 further comprises an encoder 5 for detecting the length of the rolled plate, wherein the plate thickness control module 3 is respectively connected to the encoder 5 and the thickness gauge 206, wherein the plate thickness control module 3 is mutually connected to the industrial control computer 6 and exchanges data, wherein the plate thickness control module 3 sends a speed reduction command to the rolling mill when the length of the work roll 109 from the rolling line reaches the remaining length, wherein the plate thickness control module 3 sends a speed-unchanging or delayed shutdown command to the rolling mill when the set data of the target plate thickness to be rolled is compared with the real-time data obtained from the thickness gauge 206, wherein the main control unit 2 is respectively connected to the plate thickness control module 3 and the rolling mill control unit 1 , which receives instructions from the plate thickness control module 3. The advantage of the present invention is that a kind of precision control is added. The encoder 5 is used to detect the length of the rolled plate. When the rolling mill roller 109 reaches the remaining length from the previous rolling line, the rolling mill is decelerated until it is decelerated to 50m / min. When the rolling mill is decelerated to 50m / min, the length of the rolling mill roller 109 from the previous rolling line is 10 meters. The thickness gauge 206 detects that the thickness is 10% thicker (the rolling line of the previous rolling), and then the mill is stopped after a delay of 2 seconds. If the thickness gauge 206 detects that the thickness does not reach 10% thicker, the rolling mill maintains a speed of 50m / min until the thickness gauge 206 detects that the thickness is 10% thicker, and then the mill is stopped after a delay of 2 seconds. In this way, the two adjacent rolling lines on the same side of the steel plate are only about 0.2 meters, which improves the utilization rate of materials, has a high safety factor, and does not waste materials.
[0024] Specifically, the guide roller is between the thickness gauge 206 and the entrance tension roller 105. Figure 2 Not marked, in addition, the encoder 5 provided on the plate roller 207 and the guide roller is Figure 2 Not shown, there are two thickness gauges 206, which are located on both sides of the work roll 109. Figure 2As shown, the thickness gauge 206 located on the left side of the work roll 109 is not labeled.
[0025] like Figure 2 As shown, the rolling mill includes an entry uncoiler 101 and its pressure roller 102, a telescopic guide plate 103, a leveler 104, an entry tension roller 105, a CPC 106, a wedge 107, two back rollers 108, two working rollers 109, two upward hydraulic cylinders 110, an exit tension roller 111 and its pressure roller 112. The telescopic guide plate 103, the leveler 104, the CPC 106, the two working rollers 109 and the exit tension roller 111 and its pressure roller 112 are arranged in sequence in the same direction gradually away from the entry uncoiler 101, and the entry tension roller 105 is arranged between the working roller 109 and the entry uncoiler 101. The two working rollers 109 are arranged parallel to each other, with a working gap between them, and a back roller 108 is arranged on the outer side of each of the two working rollers 109, a wedge 107 is arranged on the upper back roller 108, and two upward hydraulic cylinders 110 are arranged below the lower back roller 108. The entry uncoiler 101 is provided with the raw material of the rolled steel plate to be subjected to the first pass. The raw steel plate slides out from between the entry uncoiler 101 and its pressing roller 102, crosses the telescopic guide plate 103, is arranged by the leveler 104, passes through the CPC 106, and then is rolled through the working gap of two working rollers 109, and is coiled by the exit tension roller 111. The up-and-down movement of the push-up hydraulic cylinder 110 can adjust the width of the working gap, thereby adjusting the thickness of the rolled steel plate.
[0026] A control method for a rolling mill shutdown control system, comprising the following steps:
[0027] 1. The steel coil is loaded on the entrance uncoiler 101, and the pressure roller 102 presses the steel coil. After the steel coil is ready, the first rolling process starts: the entrance uncoiler 101 is started, and the plate head of the steel coil is sent to the exit tension roller 111. The exit tension roller 111 has a clamp to clamp the plate head. The steel plate is wound around the exit tension roller 111 for 2 to 3 turns. The upward hydraulic cylinder 110 is pushed upward to make the rolling mill roller press the steel plate. The rolling mill is started, and the thickness gauge 206 and the encoder 5 are also started. The thickness gauge 206 measures the thickness of the steel plate before and after rolling, and the encoder 5 measures the length of the steel plate before and after rolling. The encoder 5 located on the guide roller needs to be used to calculate the length, and the thickness gauge 206 located on the right side of the roller 109 needs to be used to calculate the thickness.
[0028] 2. The steel coil is rolled onto the exit tension roller 111. When the tail of the steel coil stops near the entrance tension roller 105, the rolling mill stops. The first rolling pass is completed. The head and tail of the steel coil form a rolling line. The tail of the steel coil passes through the entrance tension roller 105.
[0029] 3. Start the second rolling: the steel coil is rolled onto the entrance tension roller 105, and the encoder 5 is used to detect the length of the rolled plate. When the length of the worker roller 109 from the plate head rolling line reaches the remaining length, a speed reduction command is issued to the rolling mill. When the length of the worker roller 109 from the previous rolling line is 10 meters (at this time, the production line speed is reduced to 50m / min), the thickness gauge 206 is used to detect the thickness of the steel plate. When the real-time data of the thickness of the steel plate head exceeds 10% of the set data of the thickness before rolling, the machine is stopped for two seconds. When the real-time data of the thickness of the steel plate head measured by the thickness gauge 206 does not exceed 10% of the set data of the thickness before rolling, the speed remains unchanged. When the rolling mill stops, the second rolling is completed. It is necessary to use the encoder 5 located on the plate roller 207 to calculate the length, and use the thickness gauge 206 located on the left side of the worker roller 109 to calculate the thickness;
[0030] 4. The third rolling process starts: the steel coil is rolled onto the exit tension roller 111, and the encoder 5 is used to detect the length of the rolled plate. When the length of the work roller 109 from the plate tail rolling line reaches the remaining length, a speed reduction command is issued to the rolling mill. When the length of the work roller 109 from the previous rolling line is 10 meters (at this time, the production line speed is reduced to 50m / min), the thickness gauge 206 is used to detect the thickness of the steel plate. When the real-time data of the thickness of the steel plate tail exceeds 10% of the set data of the thickness before rolling, the machine is stopped for two seconds. When the real-time data of the thickness of the steel plate tail measured by the thickness gauge 206 does not exceed 10% of the set data of the thickness before rolling, the speed remains unchanged. When the rolling mill stops, the third rolling process is completed. It is necessary to use the encoder 5 located on the guide roller to calculate the length, and use the thickness gauge 206 located on the right side of the work roller 109 to calculate the thickness.
[0031] 5. The fourth rolling process begins, and the fourth rolling process is the same as the second rolling process;
[0032] 6. The fifth rolling pass begins. The fifth rolling pass is the same as the third rolling pass, and so on.
[0033] Specifically, the remaining length of the rolling mill is calculated by the formula (1) C = πd; (2) L = C / p*P0. In the above formula, C is the circumference, d is the diameter (the diameter of the measuring wheel installed on the encoder), π is the pi ratio, P is the number of pulses per revolution of the encoder (1000P / R), P0 is the real-time accumulated pulse output by the encoder, and L is the winding length (real-time dynamic value). The diameters of the guide roller and the plate roller 207 are used as the measuring wheel diameters, respectively, with high accuracy and small errors. It will not expand like the core shaft (the inlet tension roller 105 and the outlet tension roller 111 will expand after winding the steel plate).
[0034] The calculation formula for the remaining length mentioned above is: S = (V 2 -V0 2 ) / 2a
[0035] Where: S is the remaining length
[0036] V is the current speed (the speed after the rolling is stable, the production line starts, accelerates, and accelerates to a certain speed and maintains it, V is a certain speed)
[0037] V0=50m / min
[0038] a=40m / min / s (deceleration ratio, i.e. deceleration of 40m / min per second)
[0039] Specifically, the plate head of the steel coil is defined as Figure 2 The end of the steel coil near the exit tension roller 111 is defined as the tail of the steel coil. Figure 2 The left and right sides of the steel coil near the entrance tension roller 105 are Figure 2 Based on the benchmark.
[0040] Specifically, during the third rolling pass, when the length of the work roller 109 from the plate tail rolling line reaches the remaining length, a speed reduction command is issued to the rolling mill. When the length of the work roller 109 from the previous rolling line is 10 meters (at this time the production line speed is reduced to 50m / min), the thickness gauge 206 is used to detect the thickness of the steel plate. When the real-time data of the thickness of the steel plate tail exceeds 10% of the set data of the thickness before rolling, the machine is stopped for two seconds. When the real-time data of the thickness of the steel plate tail measured by the thickness gauge 206 does not exceed 10% of the set data of the thickness before rolling, the speed remains unchanged. When the rolling mill stops, the third rolling pass is completed (delaying 2 seconds to stop means stopping immediately after 2 seconds). Starting from the second rolling pass, the rolling mill begins to slow down when the remaining length requirement is met. At a reduction ratio of 40m / min / s, when the production line speed is reduced to 50m / min, the length of the work roller 109 from the previous rolling line is 10 meters.
[0041] The first rolling pass is the movement of the tail of the steel coil toward the head of the steel coil, the second rolling pass is the movement of the head of the steel coil toward the tail of the steel coil, the third rolling pass is the movement of the tail of the steel coil toward the head of the steel coil, the fourth rolling pass is the movement of the head of the steel coil toward the tail of the steel coil, and so on.
[0042] The reduction rate of each rolling pass is between 20-30%. The thickness gauge 206 detects that the thickness is 10% thicker, indicating that the steel plate is already thicker at the position of the thickness gauge 206, indicating that it is approaching the corresponding rolling line.
[0043] Specifically, the thickness gauge 206 is 1.9 meters away from the center line of the work roller 109, and the guide roller is 2.5 meters away from the center line of the work roller 109.
[0044] Specifically, the principle of the present invention is to monitor the length of the tail rolling line and the length of the plate head rolling line of the steel plate in real time, and to enable the rolling mill to automatically slow down to a stop in time when the length of the tail or head of the plate is controllable, thereby preventing the steel strip from exceeding the length of the tail or head of the plate, effectively saving production costs and improving the yield rate.
[0045] Based on the above scheme, if various changes or modifications to the present invention do not depart from the spirit and scope of the present invention, and if these changes and modifications fall within the scope of the claims and equivalent technologies of the present invention, the present invention is also intended to include these changes and modifications.
Claims
1. A control system for a rolling mill shutdown, comprising a rolling mill control unit (1), a main control unit (2), a plate thickness control module (3) and an industrial control computer (6), wherein thickness gauges (206) are provided at both the outlet and the inlet of the work roll (109), and characterized in that: It also includes an encoder (5) for detecting the length of the rolled plate. The plate thickness control module (3) is respectively connected to the encoder (5) and the thickness gauge (206). The plate thickness control module (3) is connected to the industrial control computer (6) and exchanges data. When the length of the work roll (109) from the rolling line reaches the remaining length, the plate thickness control module (3) sends a speed reduction command to the rolling mill. When the set data of the target plate thickness to be rolled is consistent with the thickness obtained from the thickness gauge (206), the plate thickness control module (3) sends a speed reduction command to the rolling mill. When comparing the real-time data of the rolling mill, a command to keep the speed unchanged or delay the shutdown is issued to the rolling mill. The main control unit (2) is respectively connected to the plate thickness control module (3) and the rolling mill control unit (1), and receives the command from the plate thickness control module (3); the rolling mill control unit (1) includes a frequency converter (4) and a motor (7), the frequency converter (4) is connected to the motor (7), and the main control unit (2) is connected to the frequency converter (4); the encoder (5) is respectively arranged on the guide roller and the plate shape roller (207).
2. A rolling mill shutdown control system according to claim 1, characterized in that: The encoder (5) is an Omron high-precision encoder.
3. A rolling mill shutdown control system according to claim 1, characterized in that: The thickness gauge (206) is an X-ray thickness gauge.
4. A rolling mill shutdown control system according to claim 1, characterized in that: The plate thickness control module (3) stores plate thickness setting data, and can compare the target plate thickness setting data with the real-time data obtained from the thickness gauge (206), thereby issuing a command to the rolling mill output to keep the speed constant or delay shutdown.
5. A rolling mill shutdown control system according to claim 1, characterized in that: The plate thickness control module (3) realizes its function through the plate thickness PLC.
6. A rolling mill shutdown control system according to claim 1, characterized in that: When the real-time data of the steel plate thickness measured by the thickness gauge (206) exceeds 10% of the set data of the thickness before rolling, the machine is stopped after a delay of two seconds.
7. A control method for a rolling mill shutdown control system according to any one of claims 1 to 6, characterized in that: It includes the following steps: First, the steel coil is loaded on the entrance uncoiler (101). After the steel coil is ready, the first rolling process starts: the entrance uncoiler (101) is started, the plate head of the steel coil is sent to the exit tension roller (111), the hydraulic cylinder 110 is pushed upward to make the work roller (109) press the steel plate, the rolling mill is started, the thickness gauge (206) and the encoder (5) are also started, the thickness gauge (206) respectively measures the thickness of the steel plate before and after rolling, and the encoder (5) respectively measures the length of the steel plate before and after rolling; second, the steel coil is rolled onto the exit tension roller (111), and the plate tail of the steel coil stops near the entrance tension roller (105), the rolling mill is stopped, the first rolling process is completed, the plate head and plate tail of the steel coil are formed with rolling lines, and the plate tail of the steel coil passes through the entrance tension roller (105). The steel coil is wound back and forth between the exit tension roller (111) and the entrance tension roller (105). The length of the rolled plate is detected by the encoder (5). When the length of the work roller (109) from the previous rolling line reaches the remaining length, a speed reduction command is issued to the rolling mill. When the length of the work roller (109) from the previous rolling line is 10 meters, the production line speed is reduced to 50 m / min. The thickness of the steel plate is then detected by the thickness gauge (206). When the real-time data of the steel plate thickness exceeds 10% of the set data of the thickness before rolling, the machine is stopped for two seconds. When the real-time data of the steel plate thickness measured by the thickness gauge (206) does not exceed 10% of the set data of the thickness before rolling, the speed remains unchanged.