CN112371729B - Strip breakage protection method for Sendzimir rolling mill - Google Patents
Strip breakage protection method for Sendzimir rolling mill Download PDFInfo
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- CN112371729B CN112371729B CN202010951914.1A CN202010951914A CN112371729B CN 112371729 B CN112371729 B CN 112371729B CN 202010951914 A CN202010951914 A CN 202010951914A CN 112371729 B CN112371729 B CN 112371729B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B33/00—Safety devices not otherwise provided for; Breaker blocks; Devices for freeing jammed rolls for handling cobbles; Overload safety devices
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B38/00—Methods or devices for measuring, detecting or monitoring specially adapted for metal-rolling mills, e.g. position detection, inspection of the product
Abstract
A strip breakage protection method for a Sendzimir rolling mill comprises a strip breakage detection system and a strip breakage protection system, wherein the strip breakage detection system takes the torque change rate detection of an intermediate motor of the rolling mill as core detection, and judges whether the rolling mill is in a strip breakage state or not by calculating the torque change rate of the intermediate motor and a designed judgment model; if the belt is broken, sending a belt breaking alarm signal to the control system; the control system sends an execution signal to the broken belt protection system; and after receiving the execution signal, the strip breakage protection system immediately sends an instruction to the left and right recoiling machines and the intermediate motor frequency converter to require the left and right recoiling machines to stop at an emergency stop speed, and simultaneously sends an instruction to open the rolling mill hydraulic pressing system at the fastest speed. The invention has the characteristics of high detection speed, high precision and quick alarm, brings forward the alarm for more than 1 second compared with the alarm before improvement, greatly reduces the accident probability of steel piling, roller damage and the like, and improves the economic efficiency.
Description
Technical Field
The invention belongs to the technical field of stainless steel production, and relates to a strip breakage protection method for a Gimier rolling mill.
Background
The Sendzimir rolling mill is widely applied to the stainless steel cold rolling process due to the characteristics of good rigidity, high reaction speed, high rolling precision and the like, and the strip breakage accident (especially in the process of rolling thin strips at high speed) can be avoided due to the high rolling speed and the thin thickness of rolled strip steel. As the roll system structure of the Sendzimir rolling mill is complex, once the protection is not timely in the process of strip breakage, the damaged strip steel is twisted into the roll system, the whole set of roll system can be damaged, and the long-time shutdown is caused. Therefore, the broken strip protection system of the Sendzimir rolling mill is a key subsystem in the whole rolling mill control system, and the function precision plays a decisive role in reducing the broken strip loss and shortening the broken strip processing time.
At present, the Sendzimir rolling mill adopts an external broken strip detection system, and the Sendzimir rolling mill broken strip detection system is generally as follows:
adopting a tension detection system at an inlet and an outlet of a rolling mill: judging whether the strip is broken or not by detecting the deviation value of the set tension and the actual tension at the inlet and the outlet of the rolling mill;
adopting a rolling mill entrance and exit thickness detection system: judging whether the strip is broken or not by detecting the deviation value between the set thickness and the actual thickness of the outlet and the inlet of the rolling mill;
adopting a speed detection system at an inlet and an outlet of a rolling mill: and judging whether the strip is broken or not by detecting the deviation value between the set thickness and the actual thickness of the outlet and the inlet of the rolling mill.
In the actual use process, the defect of low detection speed is found, and the strip breakage response time is generally delayed by about 2-3 seconds, so that a large number of steel piling accidents are caused, and the whole set of roller system is damaged in serious cases.
Therefore, there is a need to improve the existing broken belt detection system to increase the detection speed and reduce the occurrence of steel piling accidents.
Disclosure of Invention
The invention aims to solve the technical problem of providing a strip breakage protection method for a Gimlier rolling mill, which has the characteristics of high detection speed and high detection precision.
The technical scheme adopted by the invention for solving the technical problems is as follows: a strip breakage protection method of a Gimlier rolling mill is characterized by comprising the following steps: the strip breakage detection system takes the torque change rate detection of an intermediate motor of the rolling mill as core detection, judges whether the rolling mill is in a strip breakage state or not by calculating the torque change rate of the intermediate motor and a designed judgment model, and sends a strip breakage alarm signal to the control system if the strip breakage is judged;
the control system sends an execution signal to the broken belt protection system;
and after receiving the execution signal, the strip breakage protection system immediately sends an instruction to the left and right recoiling machines and the intermediate motor frequency converter to require the left and right recoiling machines to stop at an emergency stop speed, and simultaneously sends an instruction to open the rolling mill hydraulic pressing system at the fastest speed.
Further, the judgment model is based on three conditions: judging the thickness of the strip steel at the outlet; the second condition is to judge the speed of the strip steel, the third condition is to judge the rolling force of the strip steel, a threshold value of the torque change rate is set according to the three conditions, and when the actually detected torque change rate is larger than the threshold value of the torque change rate, the strip breakage state is judged.
Preferably, the judgment model is:
the strip steel speed is less than 100 (m/min), the outlet strip steel thickness is less than 0.8mm, the rolling force is less than 300 (ton), and the threshold value of the moment change rate is set to 65%;
the strip steel speed is less than 100 (m/min), the outlet strip steel thickness is greater than 0.8mm, the rolling force is greater than 300 (ton) and less than 400 (ton), and the threshold value of the torque change rate is set to be 55%;
the strip steel speed is more than 100 (m/min) and less than 300 (ton), the outlet strip steel thickness is less than 0.8mm, the rolling force is less than 300 (ton), and the threshold value of the torque change rate is set to be 45%;
the strip steel speed is more than 100 (m/min) and less than 300 (ton), the outlet strip steel thickness is more than 0.8mm, the rolling force is more than 300 (ton) and less than 400 (ton), and the torque change rate threshold value is set to be 35%;
the strip steel speed is greater than 400 (m/min), the outlet strip steel thickness is greater than 0.8mm, the rolling force is greater than 300 (ton) and less than 400 (ton), and the threshold value of the torque change rate is set to be 25%;
the strip steel speed is greater than 400 (m/min), the outlet strip steel thickness is greater than 0.8mm, the rolling force is greater than 400 (ton), and the torque change rate threshold value is set to be 15%.
Further, the scram rate stop is from 800 meters/minute to 0 meters/minute in 4 seconds.
Further, the detection priority is set to a first level. And may incorporate the conventional break protection methods previously described.
Further, the broken belt protection system comprises:
A. control coiling machine and middle motor converter broken belt protection system: the method mainly controls that when the strip breakage happens, a left coiling machine, a right coiling machine and a middle motor stop according to a preset special slope;
B. the hydraulic pressing system of the rolling mill breaks the protective system: the hydraulic pressing system is mainly used for unloading rolling force and opening a memorial archway at a set speed when belt breakage occurs.
Finally, the torque rate of change of the intermediate machine can also be characterized instead of the current rate of change.
Compared with the prior art, the invention has the advantages that: the method is characterized in that a detection and judgment model of the moment change rate or the current change rate of the intermediate motor of the rolling mill is added on the basis of the existing detection system, the detection priority is set as the first level, the moment change rate or the current change rate of the intermediate motor is calculated through the detection of the moment or the current of the intermediate motor, and the designed model is used for judging whether the rolling mill is in a strip breakage state or not. The invention has the characteristics of high detection speed, high precision and quick alarm, brings forward more than 1 second compared with the strip breakage alarm before improvement, greatly reduces the accident probability of steel piling, roller damage and the like, improves the economic efficiency, is not limited to Gimmer rolling mills, and can be popularized to strip breakage detection systems of all single-stand rolling mills.
Drawings
FIG. 1 is a block diagram of an improved front belt break detection system;
FIG. 2 is a block diagram of a belt breakage protection system;
FIG. 3 is a schematic diagram of the intermediate torque variation rate detection according to the present invention;
FIG. 4 is a block diagram of a new model for detecting the rate of change of the intermediate torque according to the present invention;
FIG. 5 is a graph of belt break detection data in an embodiment of the present invention.
Detailed Description
The invention is described in further detail below with reference to the following examples of the drawings.
Comparative example:
the general strip breakage detection system of the sendzimir mill obtains tension signals of an inlet and an outlet of the mill from a tension meter respectively (if no tension meter obtains current signals from a frequency converter of a coiler to be converted into tension signals), obtains thickness signals at two sides from a thickness gauge, obtains linear speeds at two sides from a laser velocimeter (if no laser velocimeter obtains linear speeds of plate rolls to calculate), and determines whether strip breakage accidents occur in the mill or not through comprehensive judgment of the signals.
Fig. 1 is a control block of a broken tape detection system of alsom (current GE), in which protection thresholds of broken tape detection systems of other used companies (such as ABB, toshiba, etc.) are slightly different, but protection gates are basically the same, and in actual control, any one of the three kinds of detection triggers causes the broken tape detection system to send out a broken tape signal.
The outlet and inlet thickness deviation signal is from an outlet and inlet thickness gauge, the outlet and inlet tension deviation is from an outlet and inlet tension gauge or is converted from an actual value of moment current of a frequency converter of a coiling machine of the outlet and inlet, and the outlet and inlet linear speed deviation is from an actual value of speed of a laser velocimeter of the outlet and inlet or a frequency converter of a plate-shaped roller of the outlet and inlet.
FIG. 2 is a block diagram of a strip breakage protection system for a rolling mill, wherein after a strip breakage signal is sent, the strip breakage protection system sends an instruction to left and right recoiling machines and a middle motor frequency converter to require the strip breakage protection system to be in an emergency stop speed (from 800 m/min to 0 m/min within 4 seconds), and simultaneously sends an instruction to enable a hydraulic pressing system to be opened at the fastest speed.
According to the experience of using the Sendzimir rolling mill in the last two decades, the biggest problem brought by directly adopting an externally-square broken strip detection system is that the detection speed is relatively slow.
Taking fig. 5 as an example, fig. 5 is a data record of belt breakage in 1 month of a certain sendzimir rolling mill, and we simulate (the system has been stopped earlier) the excitation point of belt breakage detection as point a according to an original belt breakage protection system provided by the outside, and the actual reaction point of belt breakage is point B, the time interval between the two points is about 2.3 seconds, and 2.3 seconds later, which often causes a serious steel piling accident of a unit, and the whole set of roll system is damaged in serious cases.
At the initial stage of the operation of a rolling mill, an external broken strip protection system is always adopted, and the broken strip response time is generally about 2-3 seconds, so that a large number of steel piling and roll system damage accidents are caused. According to statistics, production accidents such as steel piling, roller system damage and the like caused by untimely belt breakage protection in three years before a certain rolling mill is put into operation are counted, and direct economic loss is close to million yuan of RMB.
Examples
In view of the above situation, the technician analyzes the data records of multiple broken belts, and finds that the data which changes most intensely at the moment of broken belt is the torque (or current) of the main rolling mill motor, and taking fig. 5 as an example, it can be seen that the curve C changes most intensely among the 14 curves in the record table.
The moment of the middle motor of the rolling mill in the rolling process is analyzed according to the rolling theory and accords with the following formula:
t (intermediate moment) = T (exit moment) — T (entrance moment), so when the exit or entrance breaks, the entrance and exit tension disappears and the intermediate tension changes dramatically.
Therefore, as long as the torque change of the intermediate motor is detected, whether the belt is broken can be judged in advance, and according to the thought, through repeated tests for several years, a belt breakage detection system which takes the torque detection of the intermediate motor as a core to assist other detections is gradually established. Point a in fig. 5 is an alarm point of an original belt breakage detection system, and point C is an alarm point of belt breakage sent by the improved belt breakage detection system, and it can be seen that the alarm point of the new system is 1 second or more earlier than that of the old system.
Therefore, the strip breakage protection method of the Gimlier rolling mill comprises a strip breakage detection system and a strip breakage protection system, wherein the strip breakage detection system takes the moment change rate (or current change rate) detection of a middle motor of the rolling mill as core detection, judges whether the rolling mill is in a strip breakage state or not by calculating the moment change rate (or current change rate) of the middle motor and a designed judgment model, and sends a strip breakage alarm signal to a control system if the strip breakage is judged;
the control system sends an execution signal to the broken belt protection system;
and after receiving the execution signal, the strip breakage protection system immediately sends an instruction to the left and right recoiling machines and the intermediate motor frequency converter to require the left and right recoiling machines to stop at an emergency stop speed, and simultaneously sends an instruction to open the rolling mill hydraulic pressing system at the fastest speed.
Here, the belt breakage protection system includes:
A. control coiling machine and middle motor converter broken belt protection system: the method mainly controls that when the strip breakage happens, a left coiling machine, a right coiling machine and a middle motor stop according to a preset special slope;
B. the hydraulic pressing system of the rolling mill breaks the protective system: the hydraulic pressing system is mainly used for unloading rolling force and opening a memorial archway at a set speed when belt breakage occurs.
Typically, a scram rate stop is a drop from 800 meters/minute to 0 meters/minute in 4 seconds. The torque change rate detection priority is set to the first level.
The judgment model of the invention is based on three conditions: judging the thickness of the strip steel at the outlet; and judging the speed of the strip steel under the second condition, judging the rolling force of the strip steel under the third condition, setting a threshold value of the torque change rate (or the current change rate) according to the three conditions, and judging the strip breakage state when the actually detected torque change rate is greater than the threshold value of the torque change rate.
The method is characterized in that whether the rolling mill is in a strip breakage state or not is judged by calculating the moment change rate of the middle motor, and different threshold values are selected according to the following conditions, wherein M is a moment value, M0 is a moment threshold value, and M0 is determined according to three conditions shown in the figure 3.
One particularly preferred judgment model is:
when the speed of the strip steel is less than 100 (m/min), the thickness of the strip steel at an outlet is less than 0.8mm, and the rolling force is less than 300 (ton), the threshold value of the moment change rate is set to 65 percent;
when the speed of the strip steel is less than 100 (m/min), the thickness of the strip steel at an outlet is more than 0.8mm, and the rolling force is more than 300 (ton) and less than 400 (ton), the threshold value of the torque change rate is set to be 55 percent;
when the strip steel speed is more than 100 (m/min) and less than 300 (ton), the outlet strip steel thickness is less than 0.8mm, and the rolling force is less than 300 (ton), the threshold value of the torque change rate is set to be 45 percent;
when the strip steel speed is more than 100 (m/min) and less than 300 (m/min), the outlet strip steel thickness is more than 0.8mm, and the rolling force is more than 300 (ton) and less than 400 (ton), setting the torque change rate threshold value to 35%;
when the speed of the strip steel is more than 400 (m/min), the thickness of the strip steel at an outlet is more than 0.8mm, and the rolling force is more than 300 (ton) and less than 400 (ton), the threshold value of the torque change rate is set to be 25 percent;
when the strip steel speed is more than 400 (m/min), the outlet strip steel thickness is more than 0.8mm, and the rolling force is more than 400 (ton), the moment change rate threshold value is set to be 15%. See fig. 4.
Actual effect
After the new strip breakage detection system is adopted, the strip breakage detection time of the rolling mill is ensured to be more than 1 second ahead of the strip breakage system provided outside before improvement, and through verification of recent years, the probability of steel piling and roller damage during strip breakage is reduced by more than 50% than before by adopting the improved strip breakage detection system.
The invention is not limited to Gimlier rolling mills, and can be popularized to the strip breakage detection systems of all single-stand rolling mills.
Claims (5)
1. A strip breakage protection method of a Gimlier rolling mill is characterized by comprising the following steps: the strip breakage detection system takes the moment change rate detection of an intermediate motor of the rolling mill as core detection, judges whether the rolling mill is in a strip breakage state or not by calculating the moment change rate of the intermediate motor and a designed judgment model, and sends a strip breakage alarm signal to the control system if the strip breakage is judged;
the control system sends an execution signal to the broken belt protection system;
after receiving the execution signal, the strip breakage protection system immediately sends an instruction to the left and right recoiling machines and the intermediate motor frequency converter to require the left and right recoiling machines to stop at an emergency stop rate, and simultaneously sends an instruction to open a hydraulic pressing system of the rolling mill at the highest speed;
the judgment model is based on three conditions: judging the thickness of the strip steel at the outlet; judging the speed of the strip steel under the second condition, judging the rolling force of the strip steel under the third condition, setting a threshold value of the torque change rate according to the three conditions, and judging the strip breakage state when the actually detected torque change rate is greater than the threshold value of the torque change rate;
the judgment model is as follows:
the strip steel speed is less than 100 (m/min), the outlet strip steel thickness is less than 0.8mm, the rolling force is less than 300 (ton), and the threshold value of the moment change rate is set to 65%;
the strip steel speed is less than 100 (m/min), the outlet strip steel thickness is greater than 0.8mm, the rolling force is greater than 300 (ton) and less than 400 (ton), and the threshold value of the torque change rate is set to be 55%;
the strip steel speed is more than 100 (m/min) and less than 300 (m/min), the thickness of the strip steel at an outlet is less than 0.8mm, the rolling force is less than 300 (ton), and the threshold value of the torque change rate is set to be 45%;
the strip steel speed is more than 100 (m/min) and less than 300 (m/min), the outlet strip steel thickness is more than 0.8mm, the rolling force is more than 300 (ton) and less than 400 (ton), and the torque change rate threshold value is set to be 35%;
the strip steel speed is more than 400 (m/min), the outlet strip steel thickness is more than 0.8mm, the rolling force is more than 300 (ton) and less than 400 (ton), and the torque change rate threshold value is set to be 25%;
the strip steel speed is greater than 400 (m/min), the outlet strip steel thickness is greater than 0.8mm, the rolling force is greater than 400 (ton), and the torque change rate threshold value is set to be 15%.
2. The belt breakage protection method according to claim 1, characterized in that: the scram rate stops are from 800 meters/minute to 0 meters/minute in 4 seconds.
3. The belt breakage protection method according to claim 1, characterized in that: the detection priority is set to a first level.
4. The belt breakage protection method according to claim 1, characterized in that: the broken belt protection system comprises:
A. control coiling machine and middle motor converter broken belt protection system: the method mainly controls that when the strip breakage happens, a left coiling machine, a right coiling machine and a middle motor stop according to a preset special slope;
B. the hydraulic pressing system of the rolling mill breaks the protective system: when belt breakage occurs, a hydraulic pressing system unloads rolling force at a set speed and opens the memorial archways.
5. The belt breakage protection method according to claim 1, characterized in that: the torque rate of change of the intermediate machine is instead characterized by a current rate of change.
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| CN202010951914.1A CN112371729B (en) | 2020-09-11 | 2020-09-11 | Strip breakage protection method for Sendzimir rolling mill |
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| CN114789198B (en) * | 2021-10-14 | 2024-02-02 | 天津市新宇彩板有限公司 | Method and system for improving vibration belt breakage of main oil cylinder of cold rolling mill |
| CN114570770A (en) * | 2022-01-13 | 2022-06-03 | 贵州中铝铝业有限公司 | Equipment for preventing fire of broken strip of cold rolling mill |
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| KR20020028348A (en) * | 2000-10-09 | 2002-04-17 | 이구택 | Diagnosis method of strip breakage in cold rolling |
| CN101579706B (en) * | 2009-06-19 | 2011-04-20 | 武汉钢铁(集团)公司 | Rewinding steel band broken belt protection control method |
| CN104438360A (en) * | 2013-09-18 | 2015-03-25 | 宝钢不锈钢有限公司 | Rapid strip breakage detection and protection method and device based on rolling mill moment |
| KR20170065047A (en) * | 2015-12-02 | 2017-06-13 | 주식회사 포스코 | Apparatus for handling strip breakage in Rolling Mill System |
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