A strip speed control method and device for an annealing production line

Abstract

The present invention discloses a strip speed control method and device for an annealing production line. The control method is applied to the annealing production line to control the running speed of the strip, and the upper limit speed of the furnace area in the speed adjustment cycle is obtained through the strip reduction amount of the entrance looper and the incoming material length. The upper limit speed of the furnace area is a maximum speed that characterizes the strip pulling in the annealing furnace. When a fault occurs in the annealing production line, the fault processing time of the annealing production line is obtained. According to the fault processing time, it is determined whether pulling the strip at the upper limit speed of the furnace area will cause an entrance looper alarm. When the entrance looper alarm is not caused, the strip running in the annealing furnace is controlled at the upper limit speed of the furnace area during the speed adjustment cycle. When the entrance looper alarm may be caused, the strip entering the entrance looper is controlled to be decelerated during the speed adjustment cycle, so that the strip running speed of the annealing production line can take into account the stability of the looping amount of the entrance looper and the efficient production of the annealing furnace, thereby improving the accuracy of the strip running speed control.

Description

Technical Field

[0001] The present application relates to the technical field of strip steel running speed control, and in particular to a strip steel speed control method and device for an annealing production line. Background Art

[0002] For cold rolling continuous annealing lines, an inlet looper is installed between the annealing furnace and the inlet to ensure speed stability in the furnace zone. During normal production, the inlet looper is fully loaded. If the looper is too low, the furnace zone speed must be reduced to ensure continuous and stable operation.

[0003] The interference factors that affect the increase in furnace speed at the entrance section include: the entrance automatic step cycle, the entrance filling speed, the entrance follow-up furnace time, the entrance looper safety factor, the entrance looper length, the incoming material length, and whether re-welding is required. These interference factors all limit the furnace speed to a certain extent. However, there is currently no mature model that can be used to calculate the furnace speed limit of strip steel of different specifications, steel grades, and coil weights under complex and changing production conditions. Once an abnormal accident occurs in the entrance section when the furnace is running at high speed, such as re-welding, steel slipping, etc., it is very easy for the entrance and furnace speeds to mismatch, resulting in a "sub-healthy" state of the entrance looper volume. In severe cases, the unit will be shut down unplanned due to the low looper volume at the entrance.

[0004] Therefore, how to improve the accuracy of strip running speed control is a technical problem that needs to be solved urgently. Summary of the Invention

[0005] The present invention provides a strip steel speed control method and device for an annealing production line, which improves the accuracy of strip steel running speed control.

[0006] The embodiment of the present invention provides the following solutions:

[0007] In a first aspect, an embodiment of the present invention provides a strip speed control method for an annealing production line, which is applied to control the running speed of the strip in the annealing production line. The annealing production line includes an inlet looper and an annealing furnace arranged according to the running direction of the strip. The method includes:

[0008] Obtaining the strip reduction amount and incoming material length of the inlet looper during the speed adjustment period;

[0009] Obtaining an upper limit speed of the furnace zone during the speed adjustment period according to the strip reduction amount and the incoming material length, wherein the upper limit speed of the furnace zone is a maximum speed at which the strip is pulled in the annealing furnace;

[0010] When a fault occurs in the annealing production line, obtaining the fault processing time of the annealing production line;

[0011] determining, based on the fault handling duration, whether pulling the strip at the furnace zone upper limit speed causes an inlet loop alarm;

[0012] If not, controlling the strip steel running in the annealing furnace at the upper limit speed of the furnace zone during the speed adjustment period;

[0013] If so, the speed of the strip steel entering the entrance loop is controlled to be reduced during the speed adjustment period.

[0014] In an optional embodiment, a welding cleaning device is further provided at the entrance of the entrance looper, and the welding cleaning device is periodically controlled in a preset automatic step sequence. The step of obtaining the strip reduction amount of the entrance looper during the speed adjustment cycle includes:

[0015] Obtaining the furnace zone speed during the speed adjustment period, as well as the automatic step duration, adjacent step speed difference, automatic step speed, entry section acceleration, and adjacent step displacement of the welding cleaning equipment;

[0016] Obtaining the outlet strip displacement of the entry looper according to the furnace zone speed, the automatic step duration, the adjacent step speed difference and the entry section acceleration;

[0017] Obtaining the entry strip displacement of the entry looper according to the automatic step duration, the automatic step speed, the entry section acceleration, and the adjacent step displacement;

[0018] The strip reduction amount is obtained according to the difference between the inlet strip displacement and the outlet strip displacement.

[0019] In an optional embodiment, obtaining the speed difference between adjacent steps of the welding cleaning equipment includes:

[0020] When the strip steel is sheared and welded by the welding cleaning equipment in steps, according to the formula

[0021] Get the adjacent step speed difference Λ EN1 ;

[0022] When the strip steel is sheared and welded simultaneously by the welding cleaning equipment, according to the formula

[0023] Get the adjacent step speed difference Λ EN1 , where v F(i,1) is the furnace zone speed, v ENk The k-th automatic step at the entrance corresponds to the entrance segment speed of the entrance loop.

[0024] In an optional embodiment, obtaining adjacent step displacements of the welding cleaning device includes:

[0025] When the strip steel is sheared and welded by the welding cleaning equipment in steps, according to the formula Get the adjacent step displacement Λ EN2 ;

[0026] When the strip steel is sheared and welded simultaneously by the welding cleaning equipment, according to the formula

[0027] Get the adjacent step displacement Λ EN2 , where v F(i,1) is the furnace zone speed, v ENk is the automatic step speed corresponding to the kth automatic step at the entrance.

[0028] In an optional embodiment, obtaining the automatic step duration of the welding cleaning equipment includes:

[0029] Determining the cleaning section duration based on the cleaning section speed and cleaning section length of the welding cleaning equipment;

[0030] The automatic step duration is obtained according to the sum of the cleaning section duration and the associated processing duration, wherein the associated processing duration is the duration consumed by other processing processes other than strip cleaning on the welding cleaning equipment.

[0031] In an optional embodiment, obtaining the upper limit speed of the furnace zone in the speed adjustment cycle according to the strip reduction amount and the incoming material length includes:

[0032] Obtaining a lower limit of the length of the strip that fills the inlet looper according to the strip reduction amount and the incoming material length;

[0033] Obtaining a first limited speed according to a speed limit of the annealing furnace corresponding to the lower limit of the strip length;

[0034] Obtaining the remaining looping amount of the entry looper according to the maximum looping amount of the entry looper, the looping amount change rate and the strip reduction amount;

[0035] Obtaining a second limited speed according to a speed limit of the annealing furnace corresponding to the remaining loop amount;

[0036] The furnace zone upper limit speed is determined according to the minimum speed of the first limited speed and the second limited speed.

[0037] In an optional embodiment, obtaining the lower limit of the length of the strip that fills the inlet looper according to the strip reduction amount and the incoming material length includes:

[0038] According to the formula

[0039] Get the lower limit L of the strip length EN-stp(i,1) , where ΔL EN(i,1) is the strip reduction, v F(i,1) is the furnace zone speed, v ENk is the automatic step speed, t ENk is the automatic step duration, L EN-in(i,1) is the length of the incoming material;

[0040] Obtaining the remaining looping amount of the entry looper according to the maximum looping amount of the entry looper, the looping amount change rate, and the strip reduction amount, including:

[0041] According to the formula

[0042]

[0043] Obtain the remaining loop amount EXL EN-LP(i,1) , where a is the maximum looping amount of the entrance looper, b is the rate of change of the looping amount with the length of the strip, v F(i,1) is the furnace speed, Λ EN1 is the speed difference between adjacent steps, Λ EN2 is the displacement of adjacent steps, a EN is the entrance acceleration, t ENk is the automatic step duration, v ENk is the automatic step speed.

[0044] In an optional embodiment, the fault processing time includes a constant speed processing time and a speed reduction processing time;

[0045] Obtaining the constant speed processing time of the annealing production line, including:

[0046] According to the formula Get the constant speed processing time EXt EN1(i,1) , where v F(i,1) is the furnace speed, L ENLP(i,1) The strip steel withdrawal length of the inlet looper;

[0047] Obtaining the speed reduction processing time of the annealing production line, including:

[0048] According to the formula

[0049]

[0050] Get the speed reduction processing time EXt EN2(i,1) , where EXt EN1(i,1) is the constant speed processing time, v F(i,1) is the furnace zone speed, L ENLP(i,1) v is the length of the strip steel withdrawal; Fsdis the target value of furnace zone speed reduction, a F is the furnace zone acceleration.

[0051] In an optional embodiment, before obtaining the constant speed processing time or the speed reduction processing time of the annealing line, the method further includes:

[0052] Obtaining a preset safety factor, a maximum looping quantity, and a remaining looping quantity of the inlet loop;

[0053] The strip withdrawal length is obtained according to the product of the preset safety factor, the maximum looping amount and the remaining looping amount.

[0054] In a second aspect, an embodiment of the present invention further provides a strip speed control device for an annealing production line, which is applied to control the running speed of the strip in the annealing production line. The annealing production line includes an inlet looper and an annealing furnace arranged according to the running direction of the strip. The device includes:

[0055] A first acquisition module is used to obtain the strip reduction amount and incoming material length of the inlet looper during the speed adjustment period;

[0056] an obtaining module, configured to obtain an upper limit speed of the furnace zone in the speed adjustment period according to the strip reduction amount and the incoming material length, wherein the upper limit speed of the furnace zone is a maximum speed at which the strip is pulled in the annealing furnace;

[0057] A second acquisition module, when a fault occurs in the annealing production line, acquires the fault processing time of the annealing production line;

[0058] A determination module, configured to determine, based on the fault processing time, whether pulling the strip at the upper limit speed of the furnace zone causes the entrance looper alarm;

[0059] a first control module, configured to control the strip steel in the annealing furnace to run at the upper limit speed of the furnace zone during the speed adjustment period when it is determined that pulling the strip steel at the upper limit speed of the furnace zone does not cause the entrance looper alarm;

[0060] The second control module is used to determine that when the strip steel is pulled at the upper limit speed of the furnace zone and the entry loop alarm is caused, the speed of the strip steel entering the entry loop is reduced during the speed adjustment period.

[0061] Compared with the prior art, the strip speed control method and device of the annealing production line of the present invention has the following advantages:

[0062] The control method of the present invention is applied to an annealing production line to control the running speed of a steel strip. By obtaining the strip reduction amount and the incoming material length of an entry looper in a speed adjustment period, the upper limit speed of the furnace zone in the speed adjustment period is obtained according to the strip reduction amount and the incoming material length. The upper limit speed of the furnace zone is a maximum speed characterizing the speed at which the steel strip is pulled in the annealing furnace. When a fault occurs in the annealing production line, the fault processing time of the annealing production line is obtained. According to the fault processing time, it is determined whether pulling the steel strip at the upper limit speed of the furnace zone will cause an entry looper alarm. When no entry looper alarm is caused, the strip operation in the annealing furnace is controlled at the upper limit speed of the furnace zone in the speed adjustment period, and the steel strip can be pulled at the maximum speed for annealing. When an entry looper alarm may be caused, the speed reduction treatment of the strip entering the entry looper is controlled in the speed adjustment period, thereby reducing unplanned shutdown accidents caused by too low an entry looper amount, so that the strip operation speed of the annealing production line can take into account both sufficient and stable an entry looper amount and efficient production of the annealing furnace, thereby improving the accuracy of the strip operation speed control. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] In order to more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0064] Figure 1 A flow chart of a strip speed control method for an annealing production line provided by an embodiment of the present invention;

[0065] Figure 2 A logic diagram of a control method provided by an embodiment of the present invention;

[0066] Figure 3 A sequence diagram of automatic step speed and duration of strategy 1 provided in an embodiment of the present invention;

[0067] Figure 4 A sequence diagram of the automatic step speed and duration of strategy 2 provided in an embodiment of the present invention;

[0068] Figure 5 A sequence diagram of the automatic step speed and duration of an annealing production line provided in an embodiment of the present invention;

[0069] Figure 6-1 A length-speed curve of a steel strip reduced to 120 m / min provided by an embodiment of the present invention;

[0070] Figure 6-2 A length-speed curve of a steel strip reduced to 80 m / min provided by an embodiment of the present invention;

[0071] Figure 7-1 The upper limit speed cloud diagram of the furnace zone before optimizing the control method provided by the embodiment of the present invention;

[0072] Figure 7-2 A cloud diagram of the upper limit speed of the furnace zone after optimization of the control method provided in an embodiment of the present invention;

[0073] Figure 8 A schematic structural diagram of a strip speed control device for an annealing production line provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0074] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field fall within the scope of protection of the embodiments of the present invention.

[0075] See also Figure 1 , Figure 1 A flow chart of a strip speed control method for an annealing production line provided in an embodiment of the present invention is applied to control the running speed of the strip in the annealing production line. The annealing production line includes an inlet looper and an annealing furnace arranged according to the running direction of the strip. The method includes:

[0076] S11. Obtaining the strip reduction amount and incoming material length of the inlet looper during the speed adjustment period.

[0077] Specifically, the speed adjustment cycle represents the interval between speed adjustments for the annealing furnace zones on an annealing line and can be set based on the line's application requirements. Strip reduction represents the relative displacement of the strip at the inlet and outlet of the entry looper, and can be determined by the difference between the inlet and outlet strip displacements. The incoming length is the length of the strip fed into the entry looper during the speed adjustment cycle.

[0078] In actual applications, since the annealing production line is cyclically controlled based on a preset automatic step, each device on the production line calculates its automatic step speed according to the corresponding model to achieve automatic control. Therefore, the strip reduction will be related to the change of the automatic step. Conventional calculation methods may cause insufficient calculation accuracy of the strip reduction. Based on this, in a specific embodiment, a welding cleaning device is also provided at the entrance of the entry looper. The welding cleaning device is cyclically controlled according to the preset automatic step timing. The strip reduction of the entry looper during the speed adjustment cycle is obtained, including:

[0079] Obtain the furnace zone speed during the speed adjustment period, as well as the automatic step duration, adjacent step speed difference, automatic step speed, entrance section acceleration and adjacent step displacement of the welding cleaning equipment; obtain the exit strip displacement of the entrance looper based on the furnace zone speed, automatic step duration, adjacent step speed difference and entrance section acceleration; obtain the entrance strip displacement of the entrance looper based on the automatic step duration, automatic step speed, entrance section acceleration and adjacent step displacement; obtain the strip reduction amount based on the difference between the entrance strip displacement and the exit strip displacement.

[0080] Specifically, the welding and cleaning equipment includes a cross-cutting shear, a welding machine, a crescent shear, and a cleaning machine, which are arranged in sequence according to the running direction of the strip steel. The strip steel to be annealed is first cross-cut to make its head or tail neatly cut. Then, the head and tail of the adjacent coils of steel are welded together by the welding machine. The crescent shear shears the misaligned parts of the weld to ensure a smooth transition and connection between adjacent coils of steel with different widths. After being cleaned by the cleaning machine, the strip steel is output to the entrance looper, and part of the strip steel is filled into the entrance looper to maintain the dynamic balance of the entire production line. Please refer to Figure 3 Due to the continuous annealing process's limitations on strip speed fluctuations within the annealing furnace, the strip must be pulled within the furnace at the furnace speed. However, due to the demands of the welding and cleaning processes, the welding and cleaning equipment requires speed reduction and speed increase control to adapt to the furnace speed after buffering with the entry looper. For a 1700 continuous annealing line, for example, the entry looper's entry section automatic step details can be found in Table 1.

[0081] Table 1:

[0082]

[0083] Combine Figure 3 The speed and duration distribution of each automatic step can be obtained from Table 1, and then the displacement of the inlet and outlet strips can be calculated. For example, through formula 1:

[0084] The outlet strip displacement L can be obtained EN-out(i,1) , where v F(i,1) is the furnace speed, unit is m / min; EN1 is the speed difference between adjacent steps, unit is m / min; a EN is the inlet acceleration, in m / s 2 ;t ENk is the automatic step duration, in seconds. It can be understood that the adjacent step speed difference represents the sum of the absolute values ​​of the speed differences between adjacent automatic steps, the entry section acceleration represents the acceleration of the strip before it enters the entry looper, and the automatic step duration is the duration of the kth automatic step on the welding cleaning equipment.

[0085] Through formula 2:

[0086] The entrance strip displacement L can be obtained EN-in(i,1) , the entrance strip displacement represents the displacement of the strip at the entrance of the entrance looper during the withdrawal period, unit is m; where, Λ EN2 It is the displacement of adjacent steps, representing the sum of the absolute values ​​of the square differences between adjacent automatic steps, in units of m 2 / min 2 ; This formula is the entrance strip displacement obtained by the sum of the time of 9 automatic steps. The number of the sum of the time of the automatic steps can be set according to the actual situation.

[0087] Through formula three: ΔL EN(i,1) =L EN-out(i,1) -L EN-in(i,1) , the strip reduction ΔL can be obtained EN(i,1) The reduction of the strip steel represents the relative displacement of the strip steel in the entrance sleeve when the sleeve is withdrawn at the entrance.

[0088] In a specific embodiment, obtaining the speed difference of adjacent steps of the welding cleaning equipment includes:

[0089] When the strip steel is sheared and welded in steps by the welding cleaning equipment, according to Formula 4:

[0090] Get the adjacent step speed difference Λ EN1 ;

[0091] When the strip is sheared and welded simultaneously through the welding cleaning equipment, according to Formula 5:

[0092] Get the adjacent step speed difference Λ EN1 , where v F(i,1) is the furnace zone speed, v ENk It is the entrance segment speed of the entrance loop corresponding to the kth automatic step at the entrance.

[0093] For details, please refer to Figure 3 When the welding and cleaning equipment is used to shear and weld the strip steel in steps, it is necessary to first reduce the speed, cut the head and tail of the adjacent strip steel coils flat, then speed up and reduce the speed of the strip steel, and weld the head and tail of the adjacent strip steel coils to form a continuous strip steel. There are two common automatic step strategies in the entrance section. The strategies are as follows: Figure 3 As shown, strategy 2 is Figure 4 As shown. The main difference is that the entrance tail of strategy 1 is to the cross-cutting shear, while the entrance tail of strategy 2 is to the welding machine. Since strategy 1 involves multiple speed increases and decreases, the adjacent step speed difference Λ needs to be calculated according to the above formula 4 EN1 . Similarly, see Figure 4In strategy 2, the strip is decelerated and spun off to the welding machine. The adjacent step speed difference Λ needs to be calculated according to the above formula 5. EN1 .

[0094] In a specific embodiment, obtaining adjacent step displacements of a welding cleaning device includes:

[0095] When the strip steel is sheared and welded in steps by the welding cleaning equipment, according to Formula 6: Get the adjacent step displacement Λ EN2 ;

[0096] When the strip is sheared and welded simultaneously through the welding cleaning equipment, according to Formula 7:

[0097] Get the adjacent step displacement Λ EN2 , where v F(i,1) is the furnace zone speed, v ENk is the automatic step speed corresponding to the kth automatic step at the entrance.

[0098] For details, please refer to Figure 3-4 In strategy one, the displacement of adjacent steps is calculated according to formula six, and in strategy two, the displacement of adjacent steps is calculated according to formula seven.

[0099] In a specific embodiment, obtaining the automatic step duration of the welding cleaning equipment includes:

[0100] The cleaning section duration is determined according to the cleaning section speed and cleaning section length of the welding cleaning equipment; the automatic step duration is obtained according to the sum of the cleaning section duration and the associated processing duration, wherein the associated processing duration is the time consumed by other processing processes other than strip cleaning on the welding cleaning equipment.

[0101] For details, please refer to Table 1. The automatic steps involved in the entrance section of the annealing production line mainly include entrance tail cutting preparation, entrance tail cutting, welding preparation 1, welding preparation 2, welding, crescent cutting preparation, crescent cutting, weld low-speed cleaning section, and entrance follow-up furnace area. Except for the weld low-speed cleaning section, the speed and duration of the other automatic steps are fixed values, so the cleaning section duration needs to be accurately calculated. Taking strategy 2 as an example, according to formula 8: v EN8 =min(v F(i,1) +v add ,v c-max ), we can get the cleaning speed v EN8 , unit m / min, the cleaning section speed represents the actual speed of cleaning the weld position of the strip after deceleration, v F(i,1) is the furnace zone speed; v add v is the speed increment, ranging from 50 to 300, in m / min;c-max It is the upper limit of the speed control in the weld cleaning section, in m / min.

[0102] According to formula nine:

[0103] Get the cleaning period t EN8 .

[0104] L CL is the length of the cleaning section, in m; k v The duration of speed maintenance during the entrance acceleration is dimensionless and ranges from 0.2 to 0.8. EN is the inlet acceleration, unit is m / s 2 The automatic step duration is obtained by summing the cleaning section duration and the associated processing duration to accurately calculate the strip reduction amount. After obtaining the strip reduction amount and the incoming material length, step S12 is entered.

[0105] S12. Obtaining an upper limit speed of the furnace zone in the speed adjustment cycle according to the reduction amount of the strip and the incoming material length, wherein the upper limit speed of the furnace zone is a maximum speed of pulling the strip in the annealing furnace.

[0106] Specifically, since the strip reduction amount represents the relative displacement of the strip at the inlet and outlet of the entrance looper, and the incoming material length represents the strip length input into the entrance looper during the speed adjustment cycle, the looper amount of the speed adjustment cycle, that is, the strip length in the entrance looper, can be obtained through the strip reduction amount and the incoming material length. Since the entrance looper needs to ensure the minimum amount of looping to prevent system alarms, the upper limit speed of the furnace zone in the speed adjustment cycle can be obtained through the interpolation relationship between the looper amount and the maximum speed of the traction strip.

[0107] In actual application, since the strip annealing production line is in a dynamic adjustment state during the production process, multiple dynamic parameters are adjusted in real time based on the corresponding control model, so it is necessary to more accurately determine the upper limit speed of the furnace. Figure 2 In a specific embodiment, according to the strip reduction amount and the incoming material length, obtaining the upper limit speed of the furnace zone in the speed adjustment cycle includes:

[0108] According to the strip reduction amount and the incoming material length, the lower limit of the strip length that fills the entrance looper is obtained; according to the speed limit of the annealing furnace corresponding to the lower limit of the strip length, the first limited speed is obtained; according to the maximum looping amount of the entrance looper, the looping amount change rate and the strip reduction amount, the remaining looping amount of the entrance looper is obtained; according to the speed limit of the annealing furnace corresponding to the remaining looping amount of the looper, the second limited speed is obtained; according to the minimum speed of the first limited speed and the second limited speed, the upper limit speed of the furnace zone is determined.

[0109] Specifically, the lower limit of strip length represents the minimum strip length required to fill the entrance looper, in meters. The first speed limit represents the speed limit of the furnace zone speed corresponding to the entrance production rhythm of different incoming material lengths; through formula 10: v ENmax(i,j) =F1(L EN-STP(i,j) ), the first limited speed v can be obtained ENmax(i,j) , L EN-stp(i,1) The lower limit of strip length is L. When the furnace speed is limited by the entrance production rhythm, the lower limit of strip length L is EN-stp(i,1) and the incoming material length L stp-max(i,j) F1 is the interpolation relationship function between the lower limit of strip length and furnace speed, and the first limited speed is determined by interpolation query.

[0110] According to the reduction amount of the looper during the extraction of the inlet sleeve ΔL EN(i,1) , get the remaining amount of the entrance loop before the entrance starts filling EXL EN-LP(i,1) , according to formula 11: EXL EN-LP(i,1) =(ab·ΔL EN(i,1) ) / 100. Where: EXL EN-LP(i,1) ΔL is the remaining amount of the loop, that is, the remaining amount of the loop at the entrance before the loop is withdrawn; EN(i,1) is the reduction amount of the loop during the extraction at the entrance; a is the maximum loop amount, which is 90~99; b is the rate of change of the loop amount with the strip length, which is 0.02~0.2.

[0111] The remaining amount of the looper represents the percentage of the strip steel in the entrance looper to the total amount of the looper, with the unit being %. The second limited speed represents the speed limit value corresponding to the remaining amount of the looper, through formula 12:

[0112] v ENLPmax =F2(L ENLPmax ), the second limited speed v can be obtained ENLPmax , L ENLPmax is the remaining loop, we can let L ENLPmax =EXL EN-LP(i,1) , that is, the remaining loop amount L ENLPmax It is equal to the minimum looping amount of the looper, and F2 is the interpolation relationship function between the remaining looping amount and the furnace zone speed. The second limited speed is determined by interpolation query.

[0113] Through formula 13: v F-ENmax(i,j) =min(v ENmax(i,j) ,v ENLPmax ), obtain the upper limit speed v of the furnace zone F-ENmax(i,j) .

[0114] In a specific embodiment, according to the strip reduction amount and the incoming material length, obtaining the lower limit of the strip length that fills the inlet looper includes:

[0115] According to formula 14:

[0116] Get the lower limit of strip length L EN-stp(i,1) , where ΔL EN(i,1) is the strip reduction, v F(i,1) is the furnace zone speed, v ENk is the automatic step speed, t ENk is the automatic step duration, L EN-in(i,1) is the length of incoming material;

[0117] According to the maximum looping quantity of the entry looper, the looping quantity change rate and the strip reduction, the remaining looping quantity of the entry looper is obtained, including:

[0118] According to formula 15:

[0119]

[0120] Get the remaining loop quantity EXL EN-LP(i,1) , where a is the maximum looping amount at the entrance, b is the rate of change of looping amount with strip length, v F(i,1) is the furnace speed, Λ EN1 is the speed difference between adjacent steps, Λ EN2 is the displacement of adjacent steps, a EN is the entrance acceleration, t ENk is the automatic step duration, v ENk is the automatic step speed.

[0121] Specifically, the maximum loop amount a is usually 90 to 99, and the change rate b is usually 0.02 to 0.2. The lower limit of the strip length and the remaining loop amount can be calculated by the above formula to obtain the upper limit speed of the furnace area in the speed adjustment cycle. After obtaining the upper limit speed of the furnace area, enter step S13.

[0122] S13. When a fault occurs in the annealing production line, obtain the fault processing time of the annealing production line.

[0123] Specifically, the annealing line experiences abnormal faults, such as re-welding and steel slippage. Based on different fault types, the fault handling time can be calculated. For example, if the connection between adjacent coils of steel needs to be re-welded, the fault handling time is the re-welding time, which can be determined based on the control model corresponding to the production line.

[0124] In a specific embodiment, the fault processing time includes a constant speed processing time and a reduced speed processing time;

[0125] Get the constant speed processing time of the annealing line, including:

[0126] According to formula 16: Get the constant speed processing time EXtEN1(i,1) , where v F(i,1) is the furnace speed, L ENLP(i,1) The strip steel withdrawal length of the entrance looper;

[0127] Get the speed reduction processing time of the annealing line, including:

[0128] According to formula 17:

[0129]

[0130] Get the speed reduction processing time EXt EN2(i,1) , where EXt EN1(i,1) is the constant speed processing time, unit is s; v F(i,1) is the furnace speed, L ENLP(i,1) v is the length of the strip steel sleeve, in m; Fsd is the target value of the furnace zone speed reduction, in m / min; a F is the furnace zone acceleration, unit is m / s 2 .

[0131] Specifically, the constant speed processing time represents the longest fault processing time of the entrance section when the furnace zone does not slow down. In this process, the strip steel from the entrance loop is mainly supplied to the annealing furnace for annealing. The strip withdrawal length represents the length of the strip steel in the entrance loop that can be withdrawn by the furnace zone; the speed reduction processing time represents the longest fault processing time of the entrance section when the furnace zone slows down. In this process, the strip steel from the entrance loop is still supplied to the annealing furnace for annealing. Since the furnace zone is speeded down, the relative output strip length is less than the constant speed processing scenario. The above formula can accurately calculate the constant speed processing time and the speed reduction processing time.

[0132] In a specific embodiment, before obtaining the constant speed processing time or the speed reduction processing time of the annealing production line, the method further includes:

[0133] The preset safety factor, maximum looping quantity and remaining looping quantity of the entrance loop are obtained; and the strip withdrawal length is obtained according to the product of the preset safety factor, maximum looping quantity and remaining looping quantity.

[0134] Specifically, the preset safety factor is a safety value set based on the inlet looper being at the upper limit of the looper capacity. It is dimensionless and is used to reduce the risk of failure of the inlet looper under full load. ENLP(i,1) =k ENLP ·L MAX-ENLP EXL EN-LP(i,1) , you can get the strip sleeve length L ENLP(i,1) , calculate the fault processing time of the annealing production line based on the strip drawing length, and enter step S14 after obtaining the fault processing time.

[0135] S14. Determine, based on the fault handling duration, whether pulling the strip at the furnace zone upper limit speed causes an inlet looper alarm.

[0136] Specifically, if the fault handling time is too long, the amount of strip entering the entrance looper decreases, and the strip may be pulled at the upper limit of the furnace speed for annealing, causing the looping amount of the entrance looper to fall below the minimum value, resulting in an entrance looper alarm. Conversely, if the fault handling time is too short, no entrance looper alarm will be triggered. Therefore, whether an entrance looper alarm is triggered can be determined based on a set time. If the fault handling time is longer than the set time, it is determined that an entrance looper alarm will be triggered, and the process proceeds to step S16. Conversely, if the fault handling time is not longer than the set time, it is determined that an entrance looper alarm will not be triggered, and the process proceeds to step S15.

[0137] S15: If not, controlling the strip steel operation in the annealing furnace at the upper limit speed of the furnace zone during the speed adjustment period.

[0138] Specifically, when no entrance looper alarm is triggered, in order to improve the annealing efficiency of the strip steel, the strip steel operation in the annealing furnace is controlled at the upper limit speed of the furnace zone during the speed adjustment period.

[0139] S16. If yes, then control the speed of the strip steel entering the inlet loop to be slowed down during the speed adjustment period.

[0140] Specifically, when an entrance looper alarm may be caused, in order to ensure that the looper capacity of the entrance looper is not in a fully loaded state, the strip steel entering the entrance looper is slowed down to reduce the strip steel input into the entrance looper.

[0141] The following embodiment of the present invention takes a 1700 continuous cooling unit as an example to introduce the practical application of the speed control method. The basic parameters of the 1700 continuous cooling unit are shown in Table 2.

[0142] Table 2:

[0143]

[0144] Specifically, the 1700 continuous retreat unit inlet section automatic step is strategy 1, combined with production data to obtain Figure 5 The time series diagram of the speed and duration of the 1700 consecutive retreat automatic steps is shown.

[0145] The relationship between the furnace speed and the inlet process parameters before and after the optimization of the inlet automatic step: In order to increase the remaining number of inlet loops after the end of the inlet automatic step and improve the fault tolerance of the unit, the 1700 continuous retreat inlet automatic step was optimized. The details of the process parameters before and after the optimization are shown in Table 3.

[0146] Table 3:

[0147]

[0148] The main improvements are as follows: 1) Increase the entrance tail speed and reduce the entrance tail speed v EN1 Increase from 60m / min to 120m / min; 2) Use the same specification without cutting the crescent, and increase the crescent time t EN7 Reduced from 15.64s to 0s.

[0149] The impact of the automatic step optimization of the entrance section on the furnace zone limit speed before and after Figure 6-1 、 6-2 As shown. Figure 6-1 、 6-2 The production rhythm of the 1700 continuous annealing mill was analyzed when the furnace speed was reduced to 120m / min and 80m / min due to an entrance fault. At a 1700 continuous annealing mill speed of 320m / min and a target furnace speed reduction of 120m / min, the minimum strip length decreased from 1954.19m to 1505.73m before and after automatic step optimization at the entrance. The remaining looper capacity increased from 31.20% to 49.36%. The fault handling time for a target furnace speed reduction of 120m / min increased from 94s to 169s, and from 119s to 231s for a target furnace speed reduction of 80m / min. In the figure, curve T1 is the speed reduction processing time before optimization, T1' is the speed reduction processing time after optimization, T2 is the shortest strip length after optimization, T2' is the shortest strip length before optimization, T3 is the remaining loop amount after optimization, and T3' is the remaining loop amount before optimization; curve T4 is the speed reduction processing time before optimization, T4' is the speed reduction processing time after optimization, T5 is the shortest strip length after optimization, T5' is the shortest strip length before optimization, T6 is the remaining loop amount after optimization, and T6' is the remaining loop amount before optimization.

[0150] Analysis of the influence of process parameters of the inlet area on the furnace zone limit speed before and after optimization: by adjusting the inlet section to follow the furnace zone time t ENf Reduced from 180s to 40s, the filling speed v ENi Increased from 450m / min to 600m / min, the entrance tail speed v EN1 Increased from 60m / min to 120m / min; crescent duration t EN7 The speed of the 1700 continuous annealing furnace is reduced from 15.64s to 0s, and the relationship between the average value of the limit speed of the furnace zone of different specifications and the coil weight and the minimum sleeve quantity of the entrance looper control before and after the optimization of the entrance process parameters is obtained, as shown in the figure. Figure 7-1 、 7-2 As shown, Figure 7-1 In the middle, the furnace zone limit speed decreases gradually from area A1, area A2 and area A3; Figure 7-2The furnace zone limit speed gradually decreases from B1, B2, and B3. When the coil weights are 23.2t and 27t, respectively, and the minimum inlet looping volume is 30%, the average limit speed of the furnace zones of different specifications increases from 266m / min to 369m / min, showing a significant improvement in the optimized furnace zone limit speed.

[0151] Based on the same inventive concept as the control method, an embodiment of the present invention further provides a strip speed control device for an annealing production line, which is applied to control the running speed of the strip in the annealing production line. The annealing production line includes an inlet looper and an annealing furnace arranged according to the running direction of the strip. Figure 8 , the device comprises:

[0152] The first acquisition module 801 is used to obtain the strip reduction amount and incoming material length of the inlet looper during the speed adjustment period;

[0153] An obtaining module 802 is configured to obtain an upper limit speed of the furnace zone in the speed adjustment period according to the strip reduction amount and the incoming material length, wherein the upper limit speed of the furnace zone is the maximum speed of pulling the strip in the annealing furnace;

[0154] The second acquisition module 803 acquires the fault processing time of the annealing line when a fault occurs in the annealing line;

[0155] A determination module 804 is configured to determine, based on the fault processing time, whether pulling the strip at the upper limit speed of the furnace zone causes the entry looper alarm;

[0156] The first control module 805 is configured to control the strip running in the annealing furnace at the upper limit speed of the furnace zone during the speed adjustment period when it is determined that pulling the strip running at the upper limit speed of the furnace zone does not cause the entrance looper alarm;

[0157] The second control module 806 is used to control the speed reduction of the strip entering the entrance looper during the speed adjustment period when it is determined that the strip is being pulled at the upper limit speed of the furnace zone and causes the entrance looper alarm.

[0158] The technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0159] 1. By obtaining the strip reduction amount and incoming material length of the entrance looper during the speed adjustment cycle, the furnace zone upper limit speed of the speed adjustment cycle is obtained according to the strip reduction amount and incoming material length. The furnace zone upper limit speed is the maximum speed of pulling the strip in the annealing furnace. When a fault occurs in the annealing line, the fault processing time of the annealing line is obtained. According to the fault processing time, it is determined whether pulling the strip at the furnace zone upper limit speed will cause an entrance looper alarm. When the entrance looper alarm is not caused, the strip operation in the annealing furnace is controlled at the furnace zone upper limit speed during the speed adjustment cycle, and the strip can be pulled at the maximum speed for annealing. When the entrance looper alarm may be caused, the strip entering the entrance looper is controlled to be decelerated during the speed adjustment cycle, reducing unplanned shutdown accidents caused by too low entrance looper volume, so that the strip operation speed of the annealing line can take into account both the stable and sufficient volume of the entrance looper and the efficient production of the annealing furnace, thereby improving the accuracy of strip operation speed control on the annealing line.

[0160] 2. By quantitatively calculating the furnace zone speed limits for strip steel of varying specifications, steel grades, and coil weights under complex and variable inlet production conditions, key process parameters such as the minimum strip length required to fully fill the inlet looper and the inlet fault handling time are determined. This can guide the speed setting of the inlet and furnace sections during abnormal conditions, avoiding unplanned downtime caused by insufficient inlet looper coverage. Furthermore, it can quantitatively analyze the impact of inlet process parameters on the furnace zone speed limits, clarifying the key issues and research objectives that need to be addressed before the annealing line speed is increased.

[0161] It will be understood by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0162] The present invention is described with reference to flowcharts and / or block diagrams of methods, apparatus (modules, systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded computer, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0163] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0164] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 The steps for the function specified in one or more boxes.

[0165] Although preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they are aware of the basic inventive concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, the present invention is intended to include such changes and modifications as fall within the scope of the claims and their equivalents.

Claims

1. A strip speed control method for an annealing line, characterized in that: The method is applied to control the running speed of a steel strip in an annealing production line, wherein the annealing production line includes an inlet looper and an annealing furnace arranged according to the running direction of the steel strip. The method comprises: Obtaining the strip reduction amount and incoming material length of the inlet looper during the speed adjustment period; Obtaining an upper limit speed of the furnace zone during the speed adjustment period according to the strip reduction amount and the incoming material length, wherein the upper limit speed of the furnace zone is a maximum speed at which the strip is pulled in the annealing furnace; When a fault occurs in the annealing production line, obtaining the fault processing time of the annealing production line; determining, based on the fault handling duration, whether pulling the strip at the furnace zone upper limit speed causes an inlet loop alarm; If not, controlling the strip steel running in the annealing furnace at the upper limit speed of the furnace zone during the speed adjustment period; If so, the speed of the strip steel entering the inlet loop is reduced during the speed adjustment period; A welding cleaning device is further provided at the entrance of the entry looper. The welding cleaning device is periodically controlled with a preset automatic step sequence. The method of obtaining the strip reduction amount of the entry looper during the speed adjustment period includes: Obtaining the furnace zone speed during the speed adjustment period, as well as the automatic step duration, adjacent step speed difference, automatic step speed, entry section acceleration, and adjacent step displacement of the welding cleaning equipment; Obtaining the outlet strip displacement of the entry looper according to the furnace zone speed, the automatic step duration, the adjacent step speed difference and the entry section acceleration; Obtaining the entry strip displacement of the entry looper according to the automatic step duration, the automatic step speed, the entry section acceleration, and the adjacent step displacement; Obtaining the strip reduction amount according to the difference between the inlet strip displacement and the outlet strip displacement; The incoming material length is the length of the strip steel input into the inlet looper during the speed adjustment period; The step of obtaining the upper limit speed of the furnace zone in the speed adjustment cycle according to the strip reduction amount and the incoming material length includes: Obtaining a lower limit of the length of the strip that fills the inlet looper according to the strip reduction amount and the incoming material length; Obtaining a first limited speed according to a speed limit of the annealing furnace corresponding to the lower limit of the strip length; Obtaining the remaining looping amount of the entry looper according to the maximum looping amount of the entry looper, the looping amount change rate and the strip reduction amount; Obtaining a second limited speed according to a speed limit of the annealing furnace corresponding to the remaining loop amount; Determining the furnace zone upper limit speed according to the minimum speed of the first limited speed and the second limited speed; The fault processing time includes the constant speed processing time and the speed reduction processing time; Obtaining the constant speed processing time of the annealing production line, including: According to the formula Get the constant speed processing time EXt EN1(i,1) , where v F(i,1) is the furnace speed, L ENLP(i,1) The strip steel withdrawal length of the inlet looper; Obtaining the speed reduction processing time of the annealing production line, including: According to the formula L ENLP(i,1) =k ENLP ·L MAX-ENLP ·EXL EN-LP(i,1) Get the speed reduction processing time EXt EN2(i,1) , where EXt EN1(i,1) is the constant speed processing time, v F(i,1) is the furnace zone speed, L ENLP(i,1) v is the length of the strip steel withdrawal; Fsd is the target value of furnace zone speed reduction, a F is the furnace zone acceleration; k EXLP is the safety factor of the entrance loop; EXL EN-LP(i,1) L is the remaining amount of the entrance loop before starting to pull out the loop; MAX-ENLP Design the maximum amount of loops for the entrance loop.

2. The strip speed control method of the annealing line according to claim 1, characterized in that: The obtaining of the adjacent step speed difference of the welding cleaning equipment includes: When the strip steel is sheared and welded by the welding cleaning equipment in steps, according to the formula Get the adjacent step speed difference Λ EN1 ; When the strip steel is sheared and welded simultaneously by the welding cleaning equipment, according to the formula Get the adjacent step speed difference Λ EN1 , where v F(i,1) is the furnace zone speed, v ENk The k-th automatic step at the entrance corresponds to the entrance segment speed of the entrance loop.

3. The strip speed control method of the annealing line according to claim 1, characterized in that: The obtaining of adjacent step displacements of the welding cleaning equipment includes: When the strip steel is sheared and welded by the welding cleaning equipment in steps, according to the formula Get the adjacent step displacement Λ EN2 ; When the strip steel is sheared and welded simultaneously by the welding cleaning equipment, according to the formula Get the adjacent step displacement Λ EN2 , where v F(i,1) is the furnace zone speed, v ENk is the automatic step speed corresponding to the kth automatic step at the entrance, v ENi The filling speed.

4. The strip speed control method of the annealing line according to claim 1, characterized in that: The obtaining of the automatic step duration of the welding cleaning equipment includes: Determining the cleaning section duration based on the cleaning section speed and cleaning section length of the welding cleaning equipment; The automatic step duration is obtained according to the sum of the cleaning section duration and the associated processing duration, wherein the associated processing duration is the duration consumed by other processing processes other than strip cleaning on the welding cleaning equipment.

5. The strip steel speed control method of the annealing line according to claim 1, characterized in that: The step of obtaining a lower limit of the length of the strip that fills the inlet loop according to the strip reduction amount and the incoming material length includes: According to the formula Get the lower limit L of the strip length EN-stp(i,1) , where ΔL EN(i,1) is the strip reduction, v F(i,1) is the furnace zone speed, v ENk is the automatic step speed, t ENk is the automatic step duration, L EN-in(i,1) is the length of the incoming material; t ENf v is the time length of the entrance section following the furnace area; EN(i，1) is the filling speed; a EN is the entrance acceleration; Obtaining the remaining looping amount of the entry looper according to the maximum looping amount of the entry looper, the looping amount change rate, and the strip reduction amount, including: According to the formula Obtain the remaining loop amount EXL EN-LP(i,1) , where a is the maximum looping amount of the entrance looper, b is the rate of change of the looping amount with the length of the strip, v F(i,1) is the furnace speed, Λ EN1 is the speed difference between adjacent steps, Λ EN2 is the displacement of adjacent steps, a EN is the entrance acceleration, t ENk is the automatic step duration, v ENk is the automatic step speed.

6. A strip speed control device for an annealing production line, the device being used to implement the method according to any one of claims 1 to 5, characterized in that: The device is used to control the running speed of the strip in an annealing production line. The annealing production line includes an inlet looper and an annealing furnace arranged according to the running direction of the strip. The device includes: A first acquisition module is used to obtain the strip reduction amount and incoming material length of the inlet looper during the speed adjustment period; an obtaining module, configured to obtain an upper limit speed of the furnace zone in the speed adjustment period according to the strip reduction amount and the incoming material length, wherein the upper limit speed of the furnace zone is a maximum speed at which the strip is pulled in the annealing furnace; A second acquisition module, when a fault occurs in the annealing production line, acquires the fault processing time of the annealing production line; A determination module, configured to determine, based on the fault processing time, whether pulling the strip at the upper limit speed of the furnace zone causes the entrance looper alarm; a first control module, configured to control the strip steel in the annealing furnace to run at the upper limit speed of the furnace zone during the speed adjustment period when it is determined that pulling the strip steel at the upper limit speed of the furnace zone does not cause the entrance looper alarm; The second control module is used to determine that when the strip steel is pulled at the upper limit speed of the furnace zone and the entry loop alarm is caused, the speed of the strip steel entering the entry loop is reduced during the speed adjustment period.

Images