3 # flying shear shearing length and precision control method and bar production method

Abstract

The embodiment of the invention provides a 3 # flying shear shearing length and precision control method and a bar production method, and relates to the technical field of steel rolling bar shearing. The method for controlling the shearing length and precision of the 3 # flying shear comprises the steps that a pulse equivalent standard value is determined, the pulse equivalent standard value takes a measured value of a hot metal detector as the criterion, and after the rolling reduction of a roller is adjusted, the hot metal detector is replaced, the measured angle and sensitivity of the hot metal detector are adjusted, and the measured position of the hot metal detector is adjusted or water cooling is increased, the pulse equivalent standard value is determined; the pulse equivalent standard value is calculated according to the working roller diameter * M of the roller, and when the system operates stably, the pulse equivalent standard value is recovered based on the measured value of the hot metal detector; processing the tail steel, calculating the length of the whole steel according to the pulse equivalent standard value, calculating the number of shear knives and the length of the tail steel according to the length of the whole steel, and adjusting the segment length according to the calculated length of the tail steel to prevent the tail steel from being too long or too short. According to the 3 # flying shear method, the length and the cutting loss are reduced, and the rolling cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of bar shearing for steel rolling, and in particular to a method for controlling the shearing length and precision of a 3# flying shear and a bar production method. Background Art

[0002] With the continuous development and technological progress of the steel industry, modern steel rolling production lines have made significant progress in improving production efficiency and product quality. In particular, the application of automatic continuous rolling technology in the rolling process of bars and wires has greatly improved production efficiency. However, in the actual production process, there are still some technical difficulties to be overcome. For example, in the automatic continuous rolling process of the water-penetrating cooling process, the shearing accuracy of the flying shear is low, resulting in a large number of short lengths and increased cutting losses, which in turn affects the yield rate and negative tolerance control accuracy.

[0003] In order to ensure rolling quality and production efficiency, automatic control systems are usually used to monitor and adjust rolling parameters. However, when the rolled piece changes or individual parameters cannot be accurately obtained, these automatic control systems may find it difficult to accurately adjust the shearing parameters, thereby affecting the shearing accuracy of the flying shear. This will not only lead to inconsistent product dimensions, but also increase the scrap rate, which in turn makes it difficult to effectively control the yield rate and increase the rolling cost. In addition, poor negative tolerance control accuracy will also have an adverse effect on product output.

[0004] Therefore, under the existing technical background, how to reduce short length phenomenon and cutting loss becomes the key to improving the yield rate and controlling rolling costs. Summary of the invention

[0005] The purpose of the present invention includes providing a 3# flying shear shearing length and precision control method and a rod production method, which can reduce the short length phenomenon and cutting loss to improve the yield rate and control the rolling cost.

[0006] The embodiments of the present invention can be implemented as follows:

[0007] In a first aspect, the present invention provides a method for controlling the shearing length and precision of a 3# flying shear, comprising:

[0008] Determination of pulse equivalent standard value, pulse equivalent standard value is based on the value measured by hot metal detector. When adjusting the roll reduction, replacing hot metal detector, adjusting the hot metal detector measuring angle and sensitivity, adjusting the hot metal detector measuring position or adding water cooling, pulse equivalent standard value is calculated according to the roll working roll diameter × M, until the rolled product with qualified size is obtained and the pulse equivalent fluctuation measured by hot metal detector is less than or equal to the preset value A, the pulse equivalent standard value is restored to be based on the value measured by hot metal detector;

[0009] For tail steel processing, the length of the whole steel bar is calculated according to the pulse equivalent standard value, and the number of shearing knives and the tail steel length are calculated according to the length of the whole steel bar. At this time:

[0010] If the length fluctuation of the whole steel bar is within plus or minus two times of length and the calculated tail steel length can still be put on the cooling bed after adding two fixed lengths, the last cut will not be made;

[0011] If the calculated number of shear cuts is greater than 20 and the tail steel has a short tail, then starting from the first shear cut, each segmented steel will be reduced by one fixed length until the short tail phenomenon is eliminated;

[0012] If the length of the entire steel piece fluctuates within a range of plus or minus two times, the length of the last i-cut segments can fluctuate within a range of extending by one time or shortening by three times, so that the tail steel piece is within a preset range, where i is a positive integer less than 3.

[0013] In an optional embodiment, the pulse equivalent fluctuation refers to the maximum deviation of n consecutively measured pulse equivalents, where n≥5.

[0014] In an optional embodiment, when the pulse equivalent is based on the measurement value of the hot metal detector, if the deviation of the values ​​of the n consecutively measured pulse equivalents is greater than a preset value B, the pulse equivalent measurement results corresponding to the deviation greater than the preset value B are discarded.

[0015] In an optional implementation, the preset value B is less than 5%.

[0016] In an optional embodiment, M is any value between 103% and 105%;

[0017] And / or, the preset value A is less than 2‰.

[0018] In an optional embodiment, the pulse equivalent standard value is based on the value measured by the hot metal detector. As the pulse equivalent of the 3# flying shear gradually decreases during operation, when the pulse equivalent is reduced to a preset value C, the roller pressure is adjusted to restore the pulse equivalent to the pulse equivalent standard value.

[0019] In an optional embodiment, when the pulse equivalent is based on the value measured by the hot metal detector, the pulse equivalent is based on the average value of n pulse equivalents measured continuously, where n≥5.

[0020] In an optional embodiment, the No. 0 heat detector is installed after the No. 1 flying shear and between the No. 7 rack and the No. 8 rack.

[0021] In an optional embodiment, if the random error of the hot metal detector is large, at least one of the following AD measures may be taken:

[0022] A. Set up a fan to blow away the mist and moisture between the rolled piece and the heat inspection;

[0023] B. Check whether there is iron oxide chips accumulated in the conduit, and remove the accumulated iron oxide chips in the conduit;

[0024] C. Increase the water cooling temperature and increase the surface brightness of the rolled piece;

[0025] D. Replace thermal inspection with low temperature thermal inspection.

[0026] In a second aspect, the present invention provides a rod production method, comprising: controlling the 3# flying shear using the 3# flying shear shearing length and precision control method described in any one of the aforementioned embodiments.

[0027] The beneficial effects of the 3# flying shear shearing length and precision control method and the bar production method provided by the embodiment of the present invention include:

[0028] Compared with simply determining the pulse equivalent based on thermal inspection data or simply determining the pulse equivalent based on the roller ring diameter combined with the slip value, the use of the 3# flying shear shearing length and precision control method of the present application can reduce the short length phenomenon and cutting loss, and further reduce the rolling cost. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0030] Therefore, the following detailed description of the embodiments is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the invention. Based on the embodiments of the invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the invention.

[0031] In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside" and "outside" appear, the orientation or position relationship indicated is the orientation or position relationship in which the product of the invention is usually placed when used. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0032] In addition, the terms “first”, “second”, etc., if used, are merely used to distinguish between the descriptions and should not be understood as indicating or implying relative importance.

[0033] It should be noted that, in the absence of conflict, the features in the embodiments of the present invention may be combined with each other.

[0034] The embodiment of the present invention provides a method for controlling the shearing length and precision of a 3# flying shear, comprising:

[0035] Determination of pulse equivalent standard value, pulse equivalent standard value is based on the value measured by hot metal detector. When adjusting the roll reduction, replacing hot metal detector, adjusting the hot metal detector measuring angle and sensitivity, adjusting the hot metal detector measuring position or adding water cooling, pulse equivalent standard value is calculated according to the roll working roll diameter × M, until the rolled product with qualified size is obtained and the pulse equivalent fluctuation measured by hot metal detector is less than or equal to the preset value A, the pulse equivalent standard value is restored to be based on the value measured by hot metal detector;

[0036] For tail steel processing, the length of the whole steel bar is calculated according to the pulse equivalent standard value, and the number of shearing knives and the tail steel length are calculated according to the length of the whole steel bar. At this time:

[0037] If the length fluctuation of the whole steel bar is within plus or minus two times of length and the calculated tail steel length can still be put on the cooling bed after adding two fixed lengths, the last cut will not be made;

[0038] If the calculated number of shear cuts is greater than 20 and the tail steel has a short tail, then starting from the first shear cut, each segmented steel will be reduced by one fixed length until the short tail phenomenon is eliminated;

[0039] If the length of the entire steel piece fluctuates within a range of plus or minus two times, the length of the last i-cut segments can fluctuate within a range of extending by one time or shortening by three times, so that the tail steel piece is within a preset range, where i is a positive integer less than 3.

[0040] In an optional embodiment, the pulse equivalent fluctuation refers to the maximum deviation of n consecutively measured pulse equivalents, where n≥5.

[0041] In an optional embodiment, when the pulse equivalent is based on the measurement value of the hot metal detector, if the deviation of the values ​​of the n consecutively measured pulse equivalents is greater than a preset value B, the pulse equivalent measurement results corresponding to the deviation greater than the preset value B are discarded.

[0042] In an optional implementation, the preset value B is less than 5%.

[0043] In an optional embodiment, M is any value between 103% and 105%;

[0044] And / or, the preset value A is less than 2‰.

[0045] In an optional embodiment, the pulse equivalent standard value is based on the value measured by the hot metal detector. As the pulse equivalent of the 3# flying shear gradually decreases during operation, when the pulse equivalent is reduced to a preset value C, the roller pressure is adjusted to restore the pulse equivalent to the pulse equivalent standard value.

[0046] In an optional embodiment, when the pulse equivalent is based on the value measured by the hot metal detector, the pulse equivalent is based on the average value of n pulse equivalents measured continuously, where n≥5.

[0047] In an optional embodiment, if the random error of the hot metal detector is large, such as when more than three of the 10 pulse equivalents exceed the preset value B, at least one of the following AD measures may be taken:

[0048] A. Set up a fan to blow away the mist and moisture between the rolled piece and the heat inspection;

[0049] B. Check whether there is iron oxide chips accumulated in the conduit, and remove the accumulated iron oxide chips in the conduit;

[0050] C. Increase the water cooling temperature and increase the surface brightness of the rolled piece;

[0051] D. Replace thermal inspection with low temperature thermal inspection.

[0052] In principle, the pulse encoder of the exit rack directly and accurately reflects the rotation angle of the roll. When measuring, the rotation angle of the roll is proportional to the running length of the rolled piece, that is, the running length of the rolled piece represented by each pulse of the pulse encoder of the exit rack, that is, the pulse equivalent, is constant. The shearing length of the 3# flying shear is completely dependent on the accuracy and stability of the pulse equivalent, that is, the shearing length = pulse equivalent × number of pulses. When the speed of the exit rack remains unchanged, the size of the pulse equivalent directly affects the shearing accuracy. How to find the accurate pulse equivalent and keep the pulse equivalent stable is crucial.

[0053] There are two roll diameters in the process, namely the working roll diameter and the roll ring diameter. The exit line speed set on the rolling line is calculated according to the working roll diameter, and the actual line speed of the rolled piece is faster than the set exit line speed, because the rolled piece has a certain amount of forward slip when being squeezed through the roll, and the forward slip value is generally between 3% and 5%. Therefore, when setting the working roll diameter of the flying shear, it can be set according to the process working roll diameter × (103%-105%). The roll ring diameter is the maximum roll diameter of the installed roll, so when the roll diameter is not accurately estimated, the working roll diameter can be set according to the roll ring diameter first. When calculating the pulse equivalent in this way, the working roll diameter and the forward slip M of the roll are both estimated values ​​and cannot be accurately obtained, so there is an error.

[0054] In addition, during the steel rolling process, as time goes by, the working roll diameter may change due to the following reasons: roll reduction adjustment, roll wear, roll deformation caused by roll temperature change, etc. The pulse equivalent standard value is calculated according to the roll working roll diameter × M, and the length, speed and shear are always measured according to the set roll diameter, and the change of roll diameter cannot be automatically changed. Therefore, in the early stage of steel rolling, that is, the first steel rolling after debugging, or the first steel rolling after replacing the thermal inspection or adjusting the thermal inspection angle and sensitivity or adjusting the thermal inspection position, or the first steel rolling after adding water cooling, when the operator does not trust the thermal inspection, the pulse equivalent standard value is calculated according to the working roll diameter × M of the roll. After the roll reduction amount is adjusted and the rolled piece size is qualified, after several steels are rolled, if the measured value deviation of the pulse equivalent determined by the thermal inspection is within the preset value A, such as 2‰, it can be considered that the system operation is relatively stable and the thermal inspection measurement results are relatively accurate. At this time, the pulse equivalent standard value can be based on the measurement value of the hot metal detector. At this time, the working roll diameter can be calculated by inverse calculation based on the average value of n pulse equivalents, and the working roll diameter in the system can be corrected.

[0055] It should be noted that if the system can only calculate the pulse equivalent based on the working roll diameter and cannot directly associate the thermal detection results and the pulse equivalent, then during the steel rolling process, it is necessary to pay attention to the length measurement records. As time goes by, the operator will find that the measured pulse equivalent will become smaller and smaller, and the length of the sheared steel will become shorter and shorter. At this time, the roll diameter can be rewritten and corrected.

[0056] Furthermore, the smaller the pulse equivalent is, the smaller the roller diameter is, which may be caused by roller wear. At this time, the roller reduction can be adjusted. After the roller reduction is adjusted and the rolled piece size is qualified, after rolling several steel bars, when the thermal detection results are relatively stable, the roller diameter can be corrected.

[0057] In addition, if the pulse equivalent changes, the roller diameter can be corrected by adjusting the roller pressure to restore the pulse equivalent to its original value.

[0058] It should be noted that when the equipment is running stably, although the pulse equivalent determined according to the thermal inspection results is highly accurate and can automatically adapt to changes in roller diameter, it also has the following disadvantages:

[0059] 1. It is easy to generate random errors, making them greater than the preset value. Determining the pulse equivalent value based on the heat inspection results depends entirely on whether the head of the rolled piece can be accurately detected when it passes through the 1# and 2# hot metal detectors instantly. When the following situations occur, it may cause sudden changes in the measured value and inaccuracy:

[0060] The temperature of the workpiece head is too low, causing the head to turn black; when there is water cooling, there is too much mist or the workpiece turns black; iron oxide chips accumulate in the detection duct; the steel appears and disappears when it jumps; the HMD detection condition is not good, such as the optical path is not correct, the lens is dirty, etc., resulting in reduced sensitivity and failure to accurately detect when the steel head arrives.

[0061] The following methods can be used to compensate:

[0062] 1. When there is water cooling, add a fan to blow air along the direction of the hot test piece toward the rolled piece to disperse the mist and water vapor.

[0063] 2. Check promptly for accumulation of iron oxide filings and remove them promptly.

[0064] 3. If the process permits, increase the water cooling temperature so that the surface light of the rolled piece is not too dark.

[0065] 4. Please carefully check the environmental conditions of the HMD and try to adjust the thermal detection angle and sensitivity to ensure that it is in the best working condition. If other reasons have been tried, you can also consider replacing it with a low-temperature HMD.

[0066] 5. In the electrical system, in order to reduce the impact of random errors, the average value of multiple measurements, such as 10 times, is used as the pulse equivalent in use to eliminate the impact of sudden changes in measurements.

[0067] 6. In the electrical system, in order to eliminate the impact of sudden changes in measurement, a sudden change elimination button is added to the measurement record screen. That is to say, after ten measurement records are stable, click the sudden change elimination button to activate the sudden change elimination function. At this time, if a measurement value suddenly has an error greater than the preset value such as 5‰ from the original measurement average, it will be deleted.

[0068] In an optional embodiment, the No. 0 heat detector is installed after the No. 1 flying shear and between the No. 7 rack and the No. 8 rack.

[0069] In order to reduce the short length phenomenon and cutting loss, it is necessary to obtain a relatively accurate tail steel length, and the determination of the tail steel length is closely related to the length of the entire steel and the number of shearing knives. Under the premise of obtaining accurate pulse equivalent, the rolling line is running stably and the thermal inspection is accurate, the accurate length of the entire steel can basically be obtained.

[0070] Specifically, after stably rolling several steel bars, the operator can basically determine the length of the product that can be rolled out of the entire billet when rolling products of this specification by recording the cutting length, and can further determine that according to the set cutting length, a rolled steel bar will contain several integer multiples of length (i.e. the number of shearing knives that can be used) and the length of the end section (tail steel), i.e. the length of the entire steel bar = cutting length × number of shearing knives + length of the end section (tail steel).

[0071] It should be noted that after rolling a few steel bars, the measured average length can be entered into the system, so that the electrical system can obtain relatively accurate data.

[0072] When the number of shearing knives of the flying shear is determined, and the actual measured length of the rolling does not fluctuate much (within plus or minus two times of length), and when the rolling length can still be put on the cooling bed after extending two fixed lengths, the last knife can be left uncut to avoid a short tail when the length fluctuates. For example: Under normal circumstances, the flying shear cuts 10 knives, the breaking length is 97 meters, the fixed length is 12 meters, and the tail steel is about 90 meters; when the length fluctuates by about 20 meters, the tail steel is more than 110 meters, and the rolling can still be put on the cooling bed, then in the multiple length adjustment screen, increase the 11th knife by two times of length, so that the 11th knife does not cut within 120 meters.

[0073] When the length of the rolled piece is too long and the number of shearing cuts is greater than 20, in order to avoid a short tail, the length must be changed in the first few cuts to eliminate the short tail.

[0074] If the length of the rolled piece fluctuates by more than plus or minus two times of length (such as four times of length, about 40 meters), in order to avoid a short tail, the length of the last two / three cuts must be automatically adjusted (related to the installation position of the heat detector 0 and the rolling size. The farther the heat detector 0 is installed from the breaking shear / or the smaller the rolling size, the more remaining cuts there are; installing the heat detector 0 after the 1# flying shear, between the 7# and 8# frames, is conducive to early calculation of the total length of the entire steel, so as to intervene in the length adjustment early). Specifically, if the rolled piece is too long, the length of the last few cuts will be increased by multiples; if the rolled piece is too short, the length of the last few cuts will be reduced by multiples. The purpose is to ensure that the tail steel is on the cooling bed when the billet size changes slightly.

[0075] Tail end extension: The number of times the target length of the tail steel differs from the normal breaking length (e.g. +1 means adding a fixed length, -1 means reducing a fixed length).

[0076] The preset range of the tail steel is the tail end freedom: the number of times the actual length of the tail steel is allowed to differ from the target length of the tail steel (it cannot be a positive value. For example, -1 means the allowable deviation is 1 fixed length).

[0077] Optimize and adjust the upper / lower limit: Allows you to adjust the length of the last two / three cuts to the number of times the normal cutting length differs.

[0078] The length starts to be recorded when the rolled piece passes the 0# heat check, and the length is recorded when the tail of the rolled piece leaves the 0# heat check. At this time, the system predicts the total length of the rolled piece, and then calculates the remaining length and the number of remaining cuts based on the length that the flying shear has cut. When the tail steel exceeds the set range, the length of the remaining cuts is adjusted to ensure that the tail steel falls within the set range.

[0079] Specifically, in some embodiments: 0# hot shear is installed between 7# and 8# frames, cooling bed length = 120 meters, finished product length = 9 meters, multiple lengths = 11, additional length = 0.5 meters, shrinkage rate = 0.99, and segment length = 100.0506.

[0080] Analysis: Considering the distance of 5 meters left before and after the cooling bed, the maximum segment length can reach about 110 meters;

[0081] Considering the action cycle of the cooling bed = 3.5 seconds, the maximum rolling line speed = 18 meters, the minimum upper cooling bed segment length = 18 × 3.5 = 63 meters;

[0082] Optimization parameter setting: tail end extension = 0, that is, the target length of the tail steel is segment length = 100.0506;

[0083] The tail end degree of freedom = -2, that is, the actual length of the tail steel is allowed to differ from the target length of the tail steel by 2 times, that is, the length of the tail steel can be between 82 meters and 100 meters;

[0084] The upper limit of the optimization adjustment limit = 1, which means that the length of the last two / three cutters is allowed to be automatically adjusted to be 1 times longer than the normal breaking length, that is, the length of the last two / three cutters can be adjusted to about 109 meters.

[0085] The lower limit of the optimization adjustment limit = -3, which means that the length of the last two / three cutters is allowed to be automatically adjusted to be 3 times shorter than the normal breaking length, that is, the length of the last two / three cutters can be adjusted to about 73 meters.

[0086] According to the above method, when the tail of the rolled piece leaves the 0# heat inspection, there are 2 cuts remaining, and the tail steel is less than 18 meters. It is adjusted so that the last cut cuts about 109 meters, and the remaining 109 meters are not cut. At this time, the tail steel is about 109 meters. If there are 2 cuts remaining, and the tail steel is more than 20 meters, it is automatically adjusted so that the last two cuts are automatically shortened by corresponding times (each cut is shortened by a maximum of 3 times), so that the tail steel falls between 82 meters and 100 meters.

[0087] It should be noted that the proportional relationship between the running length of the workpiece and the rotation angle of the roller (i.e., the pulse equivalent) is affected by many factors, among which the fluctuation of the cross-sectional size of the workpiece and the temperature difference between the head and the tail will directly affect the running length of the workpiece per rotation of the roller (i.e., the pulse equivalent), thus significantly affecting the shearing accuracy and predicted length.

[0088] An embodiment of the present invention further provides a rod production method, comprising: controlling the 3# flying shear using the 3# flying shear shearing length and precision control method described in any one of the aforementioned embodiments.

[0089] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for controlling the shearing length and precision of a 3# flying shear, characterized in that: include: Determination of pulse equivalent standard value, pulse equivalent standard value is based on the value measured by hot metal detector. When adjusting the roll reduction, replacing hot metal detector, adjusting the hot metal detector measuring angle and sensitivity, adjusting the hot metal detector measuring position or adding water cooling, pulse equivalent standard value is calculated according to the roll working roll diameter × M, until the rolled product with qualified size is obtained and the pulse equivalent fluctuation measured by hot metal detector is less than or equal to the preset value A, the pulse equivalent standard value is restored to be based on the value measured by hot metal detector; For tail steel processing, the length of the whole steel bar is calculated according to the pulse equivalent standard value, and the number of shearing knives and the tail steel length are calculated according to the length of the whole steel bar. At this time: If the length fluctuation of the whole steel bar is within plus or minus two times of length and the calculated tail steel length can still be put on the cooling bed after adding two fixed lengths, the last cut will not be made; If the calculated number of shear cuts is greater than 20 and the tail steel has a short tail, then starting from the first shear cut, each segmented steel will be reduced by one fixed length until the short tail phenomenon is eliminated; If the length of the entire steel piece fluctuates within a range of plus or minus two times, the length of the last i-cut segments fluctuates between extending by one time and shortening by three times, so that the tail steel piece is within a preset range, where i is a positive integer less than 3.

2. The method for controlling the shearing length and precision of the 3# flying shear according to claim 1 is characterized in that: The pulse equivalent fluctuation refers to the maximum deviation of n pulse equivalents measured continuously, where n≥5.

3. The method for controlling the shearing length and precision of the 3# flying shear according to claim 1 is characterized in that: When the pulse equivalent is based on the value measured by the hot metal detector, if the deviation of any value among the n continuously measured pulse equivalents is greater than the preset value B, the pulse equivalent measurement result corresponding to the deviation greater than the preset value B will be discarded.

4. The method for controlling the shearing length and precision of the 3# flying shear according to claim 3 is characterized in that: The preset value B is less than 5%.

5. The method for controlling the shearing length and precision of the 3# flying shear according to claim 1 is characterized in that: M is any value from 103% to 105%; And / or, the preset value A is less than 2‰.

6. The method for controlling the shearing length and precision of the 3# flying shear according to claim 1 is characterized in that: The pulse equivalent standard value is based on the value measured by the hot metal detector. As the 3# flying shear runs, the pulse equivalent gradually decreases. When the pulse equivalent is reduced to the preset value C, the roller pressure is adjusted to restore the pulse equivalent to the pulse equivalent standard value.

7. The method for controlling the shearing length and precision of the 3# flying shear according to claim 1 is characterized in that: When the pulse equivalent is based on the value measured by the hot metal detector, the pulse equivalent is based on the average value of n pulse equivalents measured continuously, where n≥5.

8. The method for controlling the shearing length and precision of the 3# flying shear according to claim 1 is characterized in that: No. 0 heat detector is installed behind the No. 1 flying shear and between the No. 7 and No. 8 racks.

9. The method for controlling the shearing length and precision of the 3# flying shear according to claim 1 is characterized in that: If the random error of the hot metal detector exceeds the preset value, take at least one of the following AD measures: A. Set up a fan to blow away the mist and moisture between the rolled piece and the heat inspection; B. Check whether there is iron oxide chips accumulated in the conduit, and remove the accumulated iron oxide chips in the conduit; C. Increase the water cooling temperature and increase the surface brightness of the rolled piece; D. Replace thermal inspection with low temperature thermal inspection.

10. A rod production method, characterized in that: include: The 3# flying shear is controlled by using the 3# flying shear shearing length and precision control method described in any one of claims 1-9.